Sentence spacing#Digital age

{{Main|History of sentence spacing}}

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Shortly after the invention of movable type, highly variable spacing was created, which could create spaces of any size and allowed for perfectly even justification.DeVinne 1901. p. 142. Early American, English, and other European typesetters' style guides (also known as printers' rules) specified spacing standards that were all essentially identical from the 18th century onwards. These guides—e.g., Jacobi in the U.K. (1890)Jacobi 1890. and MacKellar, Harpel, and De Vinne (1866–1901) in the U.S.MacKellar 1885; Harpel 1870. p. 19; DeVinne 1901. p. 78.—indicated that sentences should be em-spaced, and that words should be 1/3 or 1/2 em-spaced. The relative size of the sentence spacing would vary depending on the size of the word spaces and the justification needs.Chicago University Press 1911. p. 101. Variable-spaced text (professionally typeset) is unlikely to result in a sentence space exactly twice the size of a word space (which can be seen with a typewriter or monospaced font). Variables such as whether a 1/3 or 1/2-word space is used, and whether the text is justified or unjustified, will vary the difference between a sentence space and word space. For most countries, this remained the standard for published work until the 20th century.Felici 2009. Felici illustrates that there are other examples of standard single word spaces used for sentence spacing in this period. Yet, even in this period, there were publishing houses that used a standard word space between sentences.

Mechanical type systems introduced near the end of the 19th century, such as the Linotype and Monotype machines, allowed for some variable sentence spacing similar to hand composition.Dodd 2006. p. 73; Mergenthaler Linotype 1940. Just as these machines revolutionized the mass production of text, the advent of the typewriter around the same time revolutionized the creation of personal and business documents. But the typewriters' mechanical limitations did not allow variable spacing—typists could only choose the number of times they pressed the space bar. Typists in some English-speaking countries initially learned to insert three spaces between sentencesOne or two spaces after a period? How about three? to approximate the wider sentence spacing used in traditional printing, but later settled on two spaces,Jury 2009. p. 58. This primarily refers to the United States and Great Britain. a practice that continued throughout the 20th century. This became known as "English spacing" and marked a divergence from French typists, who continued to use French spacing.Imprimerie nationale 1993.

In the early 20th century, some printers began using one and a half interword spaces (an "en quad") to separate sentences.Osgood 1919. This standard continued in use, to some extent, into the 1990s.Adams, et al. 1996. p. 24. Adams, Faux, and Rieber say, "For most composition, the em quad is used to indent the first line of a paragraph, the en quad is used to separate sentences, and the 3-em space is placed between words." An en is half an em and a 3-em space is a third of an em, so the space between sentences would be 1.5 times the space between words.

Magazines, newspapers, and books began to adopt the single-space convention in the United States in the 1940s and in the United Kingdom in the 1950s.Felici 2009; University of Chicago Press 2009; Williams 2003. p. 14. Typists did not move to single spacing simultaneously.

Technological advances began affecting sentence spacing methods. In 1941, IBM introduced the Executive, a typewriter capable of proportional spacing,Wershler-Henry 2005. pp. 254–255. which had been used in professional typesetting for hundreds of years. This innovation broke the hold that the monospaced font had on the typewriter, reducing the severity of its mechanical limitations. However, this innovation did not spread throughout the typewriter industry; the majority of mechanical typewriters, including all of the widely distributed models, remained monospaced, while a small minority of special models carried the innovations. By the 1960s, electronic phototypesetting systems ignored runs of white space in text. This was also true for the World Wide Web, as HTML normally ignores additional spacing,Lupton 2004. p. 165. HTML normally ignores all additional horizontal spacing between text.[http://www.tomsarazac.com/tom/opinions/space-after-periods.html#web How many spaces at the end of a sentence? One or two?] although in 2011 the CSS 2.1 standard officially added an option that can preserve additional spaces.{{cite web |title=Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification |url=http://www.w3.org/TR/CSS2/text.html#white-space-prop |date=7 June 2011 |at=16.6 |quote=pre-wrap: This value prevents user agents from collapsing sequences of white space.}} In the 1980s, desktop publishing software provided the average writer with more advanced formatting tools.Jury 2009. p. 57.

Early positions on typography (the "arrangement and appearance of text")American Medical Association 2007. p. 917. supported traditional spacing techniques in English publications. In 1954, Geoffrey Dowding's book Finer Points in the Spacing and Arrangement of Type underscored the widespread shift from a single enlarged em space to a standard word space between sentences.Dowding 1995.

With the advent of the computer age, typographers began deprecating double spacing, even in monospaced text. In 1989, Desktop Publishing by Design stated that "typesetting requires only one space after periods, question marks, exclamation points, and colons" and identified single sentence spacing as a typographic convention.Shushan and Wright 1989. p. 34. Stop Stealing Sheep & Find Out How Type Works (1993) and Designing with Type: The Essential Guide to Typography (2006) both indicate that uniform spacing should be used between words, including between sentences.Craig 2006. p. 90; Spiekermann and Ginger 1993, p. 123.

More recent works on typography weigh in strongly. Ilene Strizver, founder of the Type Studio, says: "Forget about tolerating differences of opinion: typographically speaking, typing two spaces before the start of a new sentence is absolutely, unequivocally wrong." The Complete Manual on Typography (2003) states that "The typewriter tradition of separating sentences with two-word spaces after a period has no place in typesetting" and that the single space is "standard typographic practice".Felici 2003. pp. 80–81. The Elements of Typographic Style (2004) advocates a single space between sentences, noting that "your typing as well as your typesetting will benefit from unlearning this quaint [double spacing] Victorian habit".

David Jury's book About Face: Reviving the Rules of Typography (2004)—published in Switzerland—clarifies the contemporary typographic position on sentence spacing:Jury 2004. p. 92.

Word spaces, preceding or following punctuation, should be optically adjusted to appear to be of the same value as a standard word space. If a standard word space is inserted after a full point or a comma, then, optically, this produces a space of up to 50% wider than that of other word spaces within a line of type. This is because these punctuation marks carry space above them, which, when added to the adjacent standard word spaces, combines to create a visually larger space. Some argue that the "additional" space after a comma and full point serves as a "pause signal" for the reader. But this is unnecessary (and visually disruptive) since the pause signal is provided by the punctuation mark itself.

{{Main|Sentence spacing in language and style guides}}

File:Traditional spacing examples from the 1911 Chicago Manual of Style.png

Early style guides for typesetting used a wider space between sentences than between words—"traditional spacing", as shown in the illustration to the right.De Vinne 1901; University of Chicago Press 1911; Hart 1893. During the 20th century, style guides commonly mandated two spaces between sentences for typewritten manuscripts, which were used prior to professionally typesetting the work.Garner, Newman and Jackson 2006; "So I ask you [authors]: space twice after every period", Nina K. Hoffman, "Typesetters Blues", in Rusch and Smith 1990, p. 113. As computer desktop publishing became commonplace, typewritten manuscripts became less relevant and most style guides stopped making distinctions between manuscripts and final typeset products.For example, the 15th Edition of the Chicago Manual of Style states that "A single character space, not two spaces, should be left after periods at the ends of sentences (both in manuscript and in final, published form) and after colons. University of Chicago Press 2003 Chicago Manual of Style. p. 61. In the same period, style guides began changing their guidance on sentence spacing. The 1969 edition of the Chicago Manual of Style used em spaces between sentences in its text;University of Chicago Press 1969 Manual of Style (commonly referred to as the Chicago Manual of Style, and titled thus in recent editions (first edition published in 1906)). The 1969 edition of the Manual of Style shows em spacing after sentences in the manuscript example (page 41), but single spacing in the typset example (p. 73). by the 2003 edition it had changed to single sentence spacing for both manuscript and print. By the 1980s, the United Kingdom's Hart's Rules (1983)Hart 1983 had shifted to single sentence spacing. Other style guides followed suit in the 1990s.American Sociological Association. Soon after the beginning of the 21st century, the majority of style guides had changed to indicate that only one word space was proper between sentences.Fogarty 2008. p. 85; Leonard, et al. 2009.

Modern style guides provide standards and guidance for the written language. These works are important to writers, since "virtually all professional editors work closely with one of them in editing a manuscript for publication".Lutz and Stevenson 2005. p. viii. Late editions of comprehensive style guides, such as the Oxford Style Manual (2003)Ritter 2003. The 2003 edition of the Oxford Style Manual combined the Oxford Guide to Style (first published as Horace Hart's Rules for Compositors and Readers at the University Press, Oxford in 1893) and the Oxford Dictionary for Writers and Editors (first published as the Authors' and Printers' Dictionary in 1905) Preface. in the United Kingdom and the Chicago Manual of Style (2010)University of Chicago Press Chicago Manual of Style 2010. in the United States, provide standards for a wide variety of writing and design topics, including sentence spacing.Fogarty 2008. p. 85. The majority of style guides now prescribe the use of a single space after terminal punctuation in final written works and publications. A few style guides allow double sentence spacing for draft work, and the Gregg Reference Manual makes room for double and single sentence spacing based on author preferences.Sabin 2005. pp. 5–6. Web design guides do not usually provide guidance on this topic, as "HTML refuses to recognize double spaces altogether".Lupton 2004. p. 165. These works themselves follow the current publication standard of single sentence spacing.Strunk and White 1999. (1st edition published in 1918.); Council of Science Editors 2006. (1st edition published in 1960.); American Medical Association 2007. (1st edition published in 1962.)

The European Union's Interinstitutional Style Guide (2008) indicates that single sentence spacing is to be used in all European Union publications—encompassing 23 languages.Publications Office of the European Union 2008. (1st edition published in 1997.) This manual is "obligatory" for all those in the EU who are involved in preparing EU documents and works ([http://publications.europa.eu/code/en/en-000100.htm "Welcome to the style guide!"]). It is intended to encompass 23 languages within the European Union ([http://publications.europa.eu/code/en/en-000600.htm "Foreword"]). For the English language, the European Commission's English Style Guide (2010) states that sentences are always single-spaced.European Commission Directorate-General for Translation. p. 22. (1st edition published in 1982.) "Note in particular that ... stops (. ? ! : ;) are always followed by only a single (not a double) space." The Style Manual: For Authors, Editors and Printers (2007), first published in 1966 by the Commonwealth Government Printing Office of Australia, stipulates that only one space is used after "sentence-closing punctuation" and that "Programs for word processing and desktop publishing offer more sophisticated, variable spacing, so this practice of double spacing is now avoided because it can create distracting gaps on a page."John Wiley & Sons Australia 2007. p. 153. The Commonwealth is an organization of 54 English-speaking states worldwide.

National languages not covered by an authoritative language academy typically have multiple style guides, only some of which may discuss sentence spacing. This is the case in the United Kingdom. The Oxford Style Manual (2003) and the Modern Humanities Research Association's MHRA Style Guide (2002) state that only single spacing should be used.Ritter 2003 Oxford Style Manual, 2003. p. 51. (First published as the MHRA Style Book in 1971.) "In text, use only a single word space after all sentence punctuation."; Modern Humanities Research Association 2002. p. 6. In Canada, both the English- and French-language sections of the Canadian Style, A Guide to Writing and Editing (1997), prescribe single sentence spacing.Dundurn Press 1997. p. 113. (1st edition published in 1987.); Public Works and Government Services of Canada 2010. p. 293. "17.07 French Typographical Rules—Punctuation: Adopt the following rules for spacing with punctuation marks. [table] Mark: Period, before: none, after: 1 space." In the United States, many style guides—such as the Chicago Manual of Style (2003)—allow only single sentence spacing.University of Chicago Press 2003 Chicago Manual of Style. p. 61. "2.12 A single character space, not two spaces, should be left after periods at the ends of sentences (both in manuscript and in final, published form)." p. 243. "6.11 In typeset matter, one space, not two (in other words, a regular word space), follows any mark of punctuation that ends a sentence, whether a period, a colon, a question mark, an exclamation point, or closing quotation marks." p. 243. "6.13 A period marks the end of a declarative or an imperative sentence. It is followed by a single space." The most important style guide in Italy, {{lang|it|Il Nuovo Manuale di Stile}} (2009), does not address sentence spacing,Lesina 2009. (1st edition published in 1986.) {{lang|it|"Prefazione: Il manuale intende fornire una serie di indicazioni utili per la stesura di testi di carattere non inventive, quali per esempio manuali, saggi, monografie, relazioni professionali, tesi di laurea, articoli per riviste, ecc."}} (Translation: "[S]tyle manual for academic papers, monographs, professional correspondence, theses, articles, etc.".) Carrada 2010. {{lang|it|"L'unico vero manuale di stile italiano, di cui nessun redattore può fare a meno"}}. (Translation: "The only real Italian style guide, a must-have for any writer".) The 2009 edition is itself uses single sentence spacing. but the {{lang|it|Guida di Stile Italiano}} (2010), the official guide for Microsoft translation, tells users to use single sentence spacing "instead of the double spacing used in the United States".Microsoft 2010. p. 4.1.8. {{lang|it|"Assicurarsi ad esempio che tra la fine e l'inizio di due periodi separati da un punto venga usato un unico spazio prima della frase successiva, invece dei due spazi del testo americano ... A differenza di altre lingue, non va inserito nessuno spazio prima dei segni di punteggiatura."}} (Translation: "Make sure that between two sentences separated by a period a single space is used before the second sentence, instead of the double spacing used in the United States ... Contrary to other languages, no space is to be added before punctuation marks.")

Some languages, such as French and Spanish, have academies that set language rules. Their publications typically address orthography and grammar as opposed to matters of typography. Style guides are less relevant for such languages, as their academies set prescriptive rules. For example, the {{lang|fr|Académie française}} publishes the {{lang|fr|Dictionnaire de l'Académie française}} for French speakers worldwide.Académie française 1992. French is spoken in 57 countries and territories throughout the world, including Europe, North America, and Francophone Africa. {{cite web |url=http://www.tlfq.ulaval.ca/axl/francophonie/francophonie.htm |title=Qu'est-ce que la Francophonie? |lang=fr |archive-url=https://web.archive.org/web/20110623113030/http://www.tlfq.ulaval.ca/axl/francophonie/francophonie.htm |archive-date=23 June 2011 }} The 1992 edition does not provide guidance on sentence spacing, but is single-sentence-spaced throughout—consistent with historical French spacing. The Spanish language is similar. The most important body within the Association of Spanish Language Academies, the Royal Spanish Academy, publishes the {{lang|es|Diccionario de la lengua española}}, which is viewed as prescriptive for the Spanish language worldwide.Real Academia Española 2001. p. 2. The 2001 edition does not provide sentence-spacing guidance, but is itself single-sentence-spaced. The German language manual {{lang|de|Empfehlungen des Rats für deutsche Rechtschreibung}} ("Recommendations of the Council for German Orthography"; 2006) does not address sentence spacing.Council for German Orthography 2010. The manual itself uses one space after terminal punctuation. Additionally, the Duden, the German-language dictionary most commonly used in Germany,Bibliographisches Institut AG 2010. indicates that double sentence spacing is an error.Bibliographisches Institut AG 2010. The Duden was the primary orthography and language guide in Germany until the German orthography reform of 1996 created a multinational council for German orthography for German-speaking countries—composed of experts from Germany, Austria, Liechtenstein and Switzerland. The current version of the Duden reflects the most recent opinions of this council.

A few reference grammars address sentence spacing, as increased spacing between words is punctuation in itself.Bringhurst 2004. p. 30. Bringhurst implies that additional spacing after terminal punctuation is redundant when combined with a period, question mark, or exclamation point. Other sources indicate that the function of terminal punctuation is to mark the end of a sentence and additional measures to perform the same measures are unnecessary. Most do not. Grammar guides typically cover terminal punctuation and the proper construction of sentences—but not the spacing between sentences.Baugh 2005. p. 200; Cutts 2009. p. 79; Garner 2009. p. 935; Lester 2005; Loberger 2009. p. 158; Stevenson 2005. p. 123; Straus 2009. p. 52; Strumpf. p. 408; Taggart 2009. Moreover, many modern grammar guides are designed for quick referenceBaugh 2005. p. 200; Hopper 2004; Stevenson 2005. p. 123. and refer users to comprehensive style guides for additional matters of writing style.Fogarty 2008. p. 85; Loberger 2009. p. 158. For example, the Pocket Idiot's Guide to Grammar and Punctuation (2005) points users to style guides such as the MLA Style Manual for consistency in formatting work and for all other "editorial concerns".Stevenson 2005. pp. xvi, 123. The Grammar Bible (2004) states that "The modern system of English punctuation is by no means simple. A book that covers all the bases would need to be of considerable breadth and weight and anyone interested in such a resource is advised to consult the Chicago Manual of Style."Strumpf 2004. p. 408.

{{Main|Sentence spacing in digital media}}

In the computer era, spacing between sentences is handled in several different ways by various software packages. Some systems accept whatever the user types, while others attempt to alter the spacing or use the user input as a method of detecting sentences. Computer-based word processors and typesetting software such as troff and TeX allow users to arrange text in a manner previously only available to professional typesetters.Felici 2003. 80; Fogarty 2008. p. 85; Fogarty 2009. p. 78; Fondiller and Nerone 2007. 93; Garner, Newman and Jackson 2006. 83; Modern Language Association 2009 77; Straus 2009. p. 52.

The text-editing environment in Emacs by default uses a double space following a period to identify the end of sentences unambiguously; the double-space convention prevents confusion with periods within sentences that signify abbreviations. How Emacs recognizes the end of a sentence is controlled by the settings sentence-end-double-space and sentence-end.{{cite book |last=Stallman |first=Richard |title=The GNU Emacs Manual |url=https://www.gnu.org/software/emacs/manual/html_node/emacs/Sentences.html#Sentences |publisher=Free Software Foundation |access-date=25 November 2011 |bibcode=1987gem..book.....S |year=1987}}

The Unix typesetter program Troff uses two spaces to mark the end of a sentence.{{cite web |last=Ossana |first=Joseph |title=Nroff/Troff User's Manual |url=http://heirloom.sourceforge.net/doctools/troff.pdf}} This allows the typesetter to distinguish sentence endings from abbreviations and to typeset them differently. Early versions of Troff, which only typeset in fixed-width fonts, would automatically add a second space between sentences, which were detected based on the combination of terminal punctuation and a line feed.

In the April 2020 update, Microsoft Word started highlighting two spaces after a period as an error and offers a correction of one space.{{Cite web |url=https://www.theverge.com/2020/4/24/21234170/microsoft-word-two-spaces-period-error-correction-great-space-debate |title=Microsoft Word now flags double spaces as errors, ending the great space debate |last=Warren |first=Tom |date=2020-04-24 |website=The Verge |access-date=2020-04-26}}

Multiple spaces are eliminated by default in most World Wide Web content, whether or not they are associated with sentences. There are options for preserving spacing, such as the CSS white-space property, and the <pre> tag.W3C 1999

James Felici, author of the Complete Manual of Typography, says that the topic of sentence spacing is "the debate that refuses to die … In all my years of writing about type, it's still the question I hear most often, and a search of the web will find threads galore on the subject".

Many people are opposed to single sentence spacing for various reasons. Some state that the habit of double spacing is too deeply ingrained to change.Williams 2003, p. 13. Others claim that additional space between sentences improves the aesthetics or readability of text.Williams 95, p. 1; Sabin 2005. pp. 5–6. Proponents of double sentence spacing also state that some publishers may still require double-spaced manuscript submissions from authors. A key example noted is the screenwriting industry's monospaced standard for screenplay manuscripts, Courier, 12-point font,Trotter 1998, p. 112. Trottier refers to Courier as the industry "standard". although some works on screenwriting indicate that Courier is merely preferred—proportional fonts may be used.Russin and Downs 2003, p. 17. The authors state that "Courier 12-point is preferred, although New York, Bookman, and Times will do". Allen 2001Moira Anderson Allen suggests that publishers are more interested in readable fonts as opposed to maintaining a fixed-width font standard. Some reliable sources state simply that writers should follow their particular style guide, but proponents of double spacing caution that publishers' guidance takes precedence, including those that ask for double-sentence-spaced manuscripts.Loberger 2009, p. 158; Stevenson 2005, p. 123; Sambuchino 2009, p. 10.

One of the most popular arguments against wider sentence spacing is that it was created for monospaced fonts of the typewriter and is no longer needed with modern proportional fonts.

Bringhurst 2004, p. 28;

Felici 2003, p. 80;

Fogarty 2008, p. 85;

Jury 2009, p. 56;

Shushan and Wright 1989, p. 34;

Smith 2009;

Straus 2009, p. 52;

Strizver 2010;

Walsh 2004, p. 3;

Williams 2003, p. 13.

However, proportional fonts existed together with wide sentence spacing for centuries before the typewriter and remained for decades after its invention. When the typewriter was first introduced, typists were most commonly taught to use three spaces between sentences. This gradually shifted to two spaces, while the print industry remained unchanged in its wide em-spaced sentences. Some sources now state it is acceptable for monospaced fonts to be single-spaced today,Sabin 2005, p. 5. although other references continue to specify double spacing for monospaced fonts.Garner, Newman, and Jackson 2006. "Continue the custom [of double spacing] only if you use a typewriter or the Courier font." The double-space typewriter convention has been taught in schools in typing classes and remains the practice in many cases. Some voice concern that students will later be forced to relearn how to type.Lloyd and Hallahan 2009.

Most style guides indicate that single sentence spacing is proper for final or published work today, and most publishers require manuscripts to be submitted as they will appear in publication—with single sentence spacing.University of Chicago Press 2010, p. 60; Lutz 2005, p. 200; Modern Language Association 2009, pp. 77–78. Writing sources typically recommend that prospective authors remove extra spaces before submitting manuscripts,Modern Humanities Research Association 2002, p. 6; Sabin 2005, p. 5; Felici 2003, p. 81; Fogarty also stated in Grammar Girl's Quick and Dirty Tips for Better Writing that numerous page designers have contacted her, stating that the presence of two spaces between sentences requires them to edit the pages to remove the extra spaces Fogarty 2008, p. 85. although other sources state that publishers will use software to remove the spaces before final publication.University of Chicago Press 2010, p. 83; The 16th edition of the Chicago Manual of Style instructs editors to remove extra spaces between sentences when preparing a manuscript for publication; also Weiderkehr 2009.

Claims abound regarding the legibility and readability of the single and double sentence spacing methods—by proponents on both sides. Supporters of single spacing assert that familiarity with the current standard in books, magazines, and the Web enhances readability, that double spacing looks strange in text using proportional fonts, and that the "rivers" and "holes" caused by double spacing impair readability.Williams 2003. 13; Smith 2009. Proponents of double sentence spacing state that the extra space between sentences enhances readability by providing clearer breaks between sentences and making text appear more legible.Jury 2004. 92; Williams 1995.

However, typographic opinions are typically anecdotal with no basis in evidence.Wheildon 1995. p. 13. "Opinions are not always safe guides to legibility of print",Tinker 1963. p. 50. and when direct studies are conducted, anecdotal opinions—even those of experts—can turn out to be false.Tinker 1963. pp. 88, 108, 127, 128, 153; Wheildon 1995. pp. 8, 35. Text that seems legible (visually pleasing at first glance) may be shown to actually impair reading effectiveness when subjected to scientific study.Tinker 1963. pp. 50, 108, 128. A useful example is the Helvetica font, an ubiquitous font that is considered to be visually pleasing in the construction and viewing of its characters, but has been found to impair reading effectiveness (readability). See Squire 2006. p. 36.

Direct studies on sentence spacing include those by Loh, Branch, Shewanown, and Ali (2002);Loh et al., 2002. p. 4. and Clinton, Branch, Holschuh, and Shewanown (2003);Clinton 2003. with results favoring neither single, double, nor triple spacing.Leonard, et al. 2009. The 2002 study tested participants' reading speed for passages of on-screen text with single and double sentence spacing. The authors stated that "the 'double space group' consistently took longer time to finish than the 'single space' group" but concluded that "there was not enough evidence to suggest that a significant difference exists".Loh et al., 2002. p. 4. The 2003 study analyzed on-screen single, double, and triple spacing. In both cases, the authors stated that there was insufficient evidence to draw a conclusion.Clinton 2003. The study did not find "statistically significant differences between reading time of single and double space[d] passages". Ni, Branch, Chen, and Clinton conducted a similar study in 2009 using identical spacing variables. The authors concluded that the "results provided insufficient evidence that time and comprehension differ significantly among different conditions of spacing between sentences".Ni et al. 2009. pp. 383, 387, 390. This study "explored the effects of spacing after the period on on-screen reading tasks through two dependent variables, reading time and reading comprehension". A 2018 study of 60 students found that those who used two word spaces between sentences read the same text 3% faster than with a monospaced font (Courier New).Johnson et al 2018, [https://link.springer.com/article/10.3758/s13414-018-1527-6 "Are two spaces better than one? The effect of spacing following periods and commas during reading"] (criticism: {{Cite news |url=https://www.forbes.com/sites/tarahaelle/2018/05/09/one-or-two-spaces-after-a-period-that-new-study-cant-tell-you/ |title=One Or Two Spaces After A Period? That New Study Can't Tell You |last=Haelle |first=Tara |work=Forbes |access-date=2018-08-23 |language=en}})

There are other studies that could be relevant to sentence spacing,Rhodes 1999. such as the familiarity of typographic conventions on readability. Some studies indicate that "tradition" can increase the readability of text,Tinker 1963. p. 124. and that reading is disrupted when conventional printing arrangements are disrupted or violated.Haber and Haber 1981. pp. 147–148, 152. The standard for the Web and published books, magazines, and newspapers is single sentence spacing.Williams 2003. p. 13.

David Jury's book What is Typography? notes, "Changes in spacing either between letters and words, or between the words only … do not appear to affect legibility. [These rather extraordinary conclusions are contrary to all other surveys on readability of texts.]"{{cite book |last=Jury |first=David |title=About Face: Reviving the Rules of Typography |publisher=Rotovision SA |year=2004 |isbn=2-88046-798-5 |location=Switzerland |page=52}} The bracketed words in the text are Jury's. For the rest of the quoted passage, Jury appears to have drawn on a report by Alison Shaw, Print for Partial Sight: A Research Report, Library Association, 1969, that he identifies on pages 51 and 247. In Jury's endnote on page 247, he points to "research done before, and at approximately the same time as, this 1969 report: G.W. Ovink, Legibility, Atmosphere-value, and Forms of Printing Types, Leiden, 1938. Donald Paterson, Miles A. Tinker, How to Make Type Readable, Harper & Brothers, 1949. Sir Cyril Birt, A Psychological Study of Typography, Cambridge University Press, 1959. Miles A. Tinker, Legibility of Print, Iowa State University Press, 1965. Miles A. Tinker, Bases for effective reading, University of Minnesota Press, 1965. Herbert Spencer, The Visible Word, Lund Humphries, 1968. The ATypI Legibility Research Committee initial report (no named author), Journal of Typographic Research, 1968."

File:The_river_effect_in_justified_text.jpg

A widespread observation is that increased sentence spacing creates "rivers"Dowding 1995. p. 29; Felici 2003. p. 80; Fogarty 2008. p. 85; Schriver 1997. 270; Smith 2009; Squire 2006. p. 65. or "holes"Garner 2006. p. 83; John Wiley & Sons 2007. p. 153; Jury 2009. p. 58; Jury 2004. p. 92; Rollo 1993. p. 4; Williams 2003. p. 13. within text, making it visually unattractive, distracting, and difficult to locate the end of sentences.Craig and Scala 2006. p. 64; The Design and Publishing Center, cited in Rhodes 1999; Garzia, R.P, and R. London. Vision and Reading. (1995). Mosby Publishing, St Louis. Cited in Scales 2002. p. 4. Other studies show that "irregular and uneven spacing" disrupts the text and may slow the reader; John Wiley & Sons Australia 2007. p. 270. The context of the "irregular and uneven spacing" is concerning justified text. Comprehensive works on typography describe the negative effect on readability caused by inconsistent spacing,Dowding 1995. p. 5; Jury 2004. p. 92. which is supported in a 1981 study which found that "comprehension was significantly less accurate with the river condition".Campbell, Marchetti, and Mewhort 1981. cited in Schriver 1997. p. 270. Another 1981 study on cathode-ray tube (CRT) displays concluded that "more densely packed text is read more efficiently … than is more loosely packed text".Kolers, Duchinsky, and Ferguson 1981. This statement is supported in other works as well. Canadian typographer Geoffrey Dowding suggests possible explanations of this phenomenon:

A carefully composed text page appears as an orderly series of strips of black separated by horizontal channels of white space. Conversely, in a slovenly setting the tendency is for the page to appear as a grey and muddled pattern of isolated spats, this effect being caused by the over-widely separated words. The normal, easy, left-to-right movement of the eye is slowed down simply because of this separation; further, the short letters and serifs are unable to discharge an important function – that of keeping the eye on "the line". The eye also tends to be confused by a feeling of vertical emphasis, that is, an up & down movement, induced by the relative isolation of the words & consequent insistence of the ascending and descending letters. This movement is further emphasized by those "rivers" of white which are the inseparable & ugly accompaniment of all carelessly set text matter.Dowding 1995. pp. 5–6, 29.

• Leading
• Scriptio continua

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• {{cite book |title= Essentials of English Grammar: The Quick Guide to Good English|edition=3rd|last= Baugh|first= L. Sue|year= 2005|publisher=McGraw Hill|location= New York|isbn=978-0-07-145708-8|at=176 pages|ref=Bau05}}
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• {{cite book|title= The Practical Printer: A Book of Instruction for Beginners; a Book of Reference for the More Advanced|edition= 3rd|last= Bishop|first= Henry Gold|year= 1895|publisher= Oneonta, N.Y., H. G. Bishop|location= Albany|url= https://archive.org/details/practicalprinter00bishrich|ref= Bis95}}
• {{cite journal |last1= Black|first1= Allison|last2= Watts|first2= Darren|year= 1993|title= Proofreading Monospaced and Proportionally-spaced Typefaces|journal= Visible Language|volume= 27|issue= 3|pages= 364–377|ref=Bla93}}
• {{cite web| title= How Many Spaces After a Period? Ending the Debate| last= Bricker| first= Dave| url= http://theworldsgreatestbook.com/how-many-spaces-after-a-period/| date= 27 March 2013| access-date= 29 March 2013| ref= bri13| archive-date= 17 April 2020| archive-url= https://web.archive.org/web/20200417102326/http://theworldsgreatestbook.com/how-many-spaces-after-a-period/| url-status= dead}}
• {{cite book |title= The Elements of Typographic Style|edition= 3.0|author-link1= Robert Bringhurst|last= Bringhurst|first= Robert|year= 2004|publisher= Hartley & Marks|location= Washington and Vancouver|isbn= 978-0-88179-206-5|at=352 pages|ref=Bri04}}
• {{cite journal |doi= 10.1080/00140138108924885 |last1= Campbell|first1= A.J.|last2= Marchetti|first2= F.M.|last3= Mewhort|first3= D.J.K.|year= 1981|title= Reading Speed and Text Production: A Note on Right-Justification Techniques|journal= Ergonomics|volume= 24|issue= 8|pages= 633–640|ref=Cam81}}
• {{cite web|url= http://www.mestierediscrivere.com/index.php/articolo/bibliografia/|title= Il mio scaffale: i libri più utili per lo scrittore professionale|author= Carrada, Luisa|year= 2010|work= Il Mestiere di Scrivere|language= it|access-date= 19 May 2010|ref= Car10|archive-url= https://web.archive.org/web/20100214162748/http://www.mestierediscrivere.com/index.php/articolo/bibliografia|archive-date= 14 February 2010|url-status= dead}}
• {{cite book|title=The AP [Associated Press] Stylebook and Briefing on Media Law|edition=44th|editor1-first=Darrell|editor1-last=Christian|editor2-first=Sally|editor2-last=Jacobsen|editor3-first=David|editor3-last=Minthorn|year=2009|publisher=Basic Books|location=Philadelphia|isbn=978-0-465-01262-6|at=[https://archive.org/details/associatedpress20000unse_e4a0/page/n419 416]|ref=Jac09|url=https://archive.org/details/associatedpress20000unse_e4a0|url-access=limited}}
• {{cite conference |last1= Clinton|first1= Gregory|last2= Branch|first2=Robert Maribe|last3= Holschuh|first3= D.|last4= Shewanown|first4= S.|year= 2003|title= Online Reading Performance Time as a Function of Text Layout: Roundtable Paper|conference=2003 AECT Leadership & Technology International Convention, Anaheim, Ca|ref= Cli03}}
• {{cite book |title= The Bluebook: A Uniform System of Citation|editor1= Columbia Law Review|editor2= Harvard Law Review|editor3= University of Pennsylvania Law Review|editor4= Yale Law review|year= 2005|publisher= The Harvard Law Review Association|location= Massachusetts |ref=Col05}}
• {{cite web |url=http://www.neue-rechtschreibung.de/regelwerk.pdf |title=Deutsche Rechtschreibung |access-date=19 January 2010 |last=Council for German Orthography |language=de |trans-title=German Orthography |ref=Cou10 |url-status=dead |archive-url=https://web.archive.org/web/20120125014532/http://www.neue-rechtschreibung.de/regelwerk.pdf |archive-date=25 January 2012 }}
• {{cite book|title= Designing With Type: The Essential Guide to Typography|url= https://archive.org/details/designingwithtyp0000crai|url-access= registration|edition= 5th|last1= Craig|first1= James|last2= Scala|first2= Irene Korol|year= 2006|publisher= Watson-Guptill|location= New York|isbn= 978-0-8230-1413-2|at= [https://archive.org/details/designingwithtyp0000crai/page/176 176] pages|ref= Cra06}}
• {{cite book |title= Oxford Guide to Plain English|edition= Third|last= Cutts|first= Martin|year= 2009|publisher= Oxford University Press|location= New York|isbn= 978-0-19-955850-6|ref=Cut09}}
• {{cite book|title= The Practice of Typography: Correct Composition: A Treatise on Spelling Abbreviations, the Compounding and Division of Words, the Proper Use of Figures and Numerals, Italic and Capital Letters, Notes, Etc., With Observations on Punctuation and Proof-Reading|url= https://archive.org/details/ost-design-the_practice_of_typography|edition= Second|last= De Vinne|first= Theodore Low|year= 1901|publisher= Century Company|location= New York|ref= DeV01}}
• {{cite book |title= From Gutenberg to Open Type: An Illustrated History of Type from the Earliest Letterforms to the Latest Digital Fonts |last= Dodd|first= Robin|year= 2006|publisher= Hartley & Marks|location= Vancouver|isbn= 978-0-88179-210-2|at=192 pages|ref=Dod06}}
• {{cite book |title= Finer Points in the Spacing & Arrangement of Type|edition= Revised|last= Dowding|first= Geoffrey|year= 1995|publisher= Hartley & Marks Publishers|location= Vancouver, BC|isbn= 978-0-88179-119-8|at=90 pages|ref=Dow95}}
• {{cite book|title= The Canadian Style: A Guide to Writing and Editing|year= 1997|last= Dundurn Press in Co-operation with Public Works and the Government Services Canada Translation Bureau|publisher= J. Kirk Howard|location= Toronto and Oxford|isbn= 978-1-55002-276-6|at= [https://archive.org/details/canadianstylegui0000unse/page/312 312] pages|ref= Dun97|url= https://archive.org/details/canadianstylegui0000unse|url-access= registration}}
• {{cite book| url=https://books.google.com/books?id=ewSglB2f7qYC&pg=PA45| title=Glossary of Typesetting Terms| last1=Eckersley| first1=Richard| last2=Ellertson| first2=Charles M.| last3=Angstaldt| first3=Richard| last4=Hendel| first4=Richard| publisher=University of Chicago Press| year=1994| isbn=978-0-226-18371-8| ref=Eck94}}
• {{cite book |title= The Economist Style Guide|last=Economist|year= 2005|publisher= Profile Books|location= London|isbn= 978-1-86197-916-2|at=256 pages |ref=Eco05}}
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• {{cite book |title= The Copyeditor's Handbook: A Guide for Book Publishing and Corporate Communications|edition= 2nd|last= Einsohn|first= Amy|year= 2006|publisher= University of California Press|location= Berkeley, Los Angeles, London|isbn=978-0-520-24688-1|at=574 pages |ref=Ein06}}
• {{cite web |url=http://ec.europa.eu/translation/writing/style_guides/english/style_guide_en.pdf |title=English Style Guide: A Handbook for Authors and Translators in the European Commission |author=European Commission Directorate-General for Translation |date=April 2010 |publisher=European Commission |access-date=12 May 2010 |ref=Eur10 |url-status=dead |archive-url=https://web.archive.org/web/20101205092625/http://ec.europa.eu/translation/writing/style_guides/english/style_guide_en.pdf |archive-date=5 December 2010 }}
• {{cite book |title= The Complete Manual of Typography|last1= Felici|first1= James|year= 2003|publisher= Peachpit Press|location= Berkeley, CA|isbn= 978-0-321-12730-3|at=384 pages |ref= Fel03}}
• {{cite web|url= http://www.creativepro.com/article/double-space-or-not-double-space|title= To Double-Space or Not to Double-Space|author= Felici, James|date= 24 August 2009|work= CreativePro.com|publisher= Printingforless.com and CreativePro.com31 March 2010|ref= Fel09}}
• {{cite book |title= How Not to Write a Screenplay: 101 Common Mistakes Most Screenwriters Make|last= Flinn|first= Denny Martin|year= 1999|publisher= Crown Publishing|location= New York|isbn= 978-1-58065-015-1|at=240 pages |ref= Fli99}}
• {{cite book|title= Grammar Girl's Quick and Dirty Tips for Better Writing|author-link1= Mignon Fogarty|last= Fogarty|first= Mignon|year= 2008|publisher= Holt Paperbacks|location= New York|isbn= 978-0-8050-8831-1|at= 240|ref= Fog08|url= https://archive.org/details/grammargirlsquic0000foga|url-access= limited}}
• {{cite book |title= The Grammar Devotional: Daily Tips for Successful Writing from Grammar Girl|last= Fogarty|first= Mignon|year= 2009|publisher= Holt Paperbacks|location= New York|isbn= 978-0-8050-9165-6|ref=Fog09}}
• {{cite book|title= Health Professionals Style Manual|url= https://archive.org/details/healthprofession00faan|url-access= limited|last1= Fondiller|first1= Shirley|last2= Nerone|first2= Barbara J.|year= 2007|publisher= Springer Publishing|location= New York|isbn= 978-0-8261-0207-2|at= [https://archive.org/details/healthprofession00faan/page/n165 152] pages|ref= Ner07}}
• {{cite web|url= https://www.gnu.org/prep/standards/html_node/Comments.html|title= 5.2 Commenting Your Work|work= GNU Coding Standards|publisher= Free Software Foundation|date= 12 April 2010|access-date= 17 May 2010|ref= Fre10}}
• {{cite book|title= Garner's Modern American Usage|url= https://archive.org/details/garnersmodername0003garn|url-access= registration|edition= 3rd|last= Garner|first= Bryan A.|year= 2009|publisher= Oxford University Press|location= Oxford|isbn= 978-0-19-538275-4|ref= Gar09}}
• {{cite book|title= The Redbook: A Manual on Legal Style|edition= 2nd|last1= Garner|first1= Bryan A.|first2= Jeff|last2= Newman|first3= Tiger|last3= Jackson|year= 2006|publisher= Thompson West|isbn= 978-0-314-16891-7|at= 1008|ref= Gar06|url= https://archive.org/details/redbook_gar_2006_00_9936|url-access= limited}}
• {{cite journal |last1= Haber|first1= Ralph Norman|last2= Haber|first2= Lyn R.|year= 1981|title= Visual Components of the Reading Process|journal= Visible Language|volume= 15|issue= 2|pages= 147–182|ref=Hab81}}
• {{cite web|url= http://www.dynamicgraphics.com/dgm/Article/28654/|archive-url= https://web.archive.org/web/20060613103135/http://www.dynamicgraphics.com/dgm/Article/28654|url-status= dead|archive-date= 2006-06-13|title= Typographic Details|author= Haley, Allan|date= June–July 2006|work= Dynamic Graphics|publisher= WebMediaBrands Inc|access-date= 18 July 2010|ref= Hal06}}
• {{cite book|title= Hart's Rules for Compositors and Readers: Which are to be Observed in All Cases Where No Special Instructions are Given|url= http://www.ritter.org.uk/H&C/H_edns/H_01e1893.html|archive-url= https://archive.today/20030503052410/http://www.ritter.org.uk/H&C/H_edns/H_01e1893.html|url-status= usurped|archive-date= 3 May 2003|access-date= 24 May 2010|edition= First|author-link1= Horace Hart|last= Hart|first= Horace|year= 1893|publisher= Clarendon Press|location= Oxford|ref= Har93}}
• {{cite web |url= http://www.ritter.org.uk/H&C/H_edns/H_39e1983.html |title= Hart's Rules for Compositors and Readers at the University Press, Oxford |edition= Thirty-ninth |author= Hart, Horace |year= 1983 |publisher= Oxford Editorial |access-date= 24 May 2010 |ref= Har83 |archive-url= https://web.archive.org/web/20101130000917/http://www.ritter.org.uk/H%26C/H_edns/H_39e1983.html |archive-date= 30 November 2010 |url-status= usurped }}
• {{cite book|title= Harpel's Typograph, or Book of Specimens Containing Useful Information, Suggestions and a Collection of Examples of Letterpress Job Printing Arranged for the Assistance of Master Printers, Amateurs, Apprentices, and Others|last= Harpel|first= Oscar|year= 1870|publisher= Cincinnati Press|url= https://archive.org/details/harpelstypograph00harp|ref= Har70}}
• {{cite journal |last1= Hartley|first1= James|year= 1980|title= Spatial Cues in Text|journal= Visible Language|volume= 14|issue= 1|pages= 62–79|ref=Har80}}
• {{cite book |title= A Pocket Guide to Correct Grammar|edition= 4th|last1=Hopper|first1=Vincent F.|last2=Gale|first2=Cedric|last3=Foote|first3=Ronald C.|last4=Griffith|first4=B.W.|year=2004|publisher=Barron's Educational Series|isbn=978-0-7641-2690-1|at=208 pages |ref=Hop04}}
• {{cite book |title= Lexique des règles typographiques en usage à l'Imprimerie nationale (in French)|edition= 3ème édition|last= Imprimerie nationale|year= 1993|publisher= Imprimerie nationale|ref= Imp93}}
• {{cite book |title= Some Notes on Books and Printing; a Guide for Authors, Publishers, & Others|edition= New & Enlarged|last= Jacobi|first= Charles Thomas|year= 1890|publisher= C. Wittingham|location= London|ref= Jac90}}
• {{cite book |title= About Face: Reviving the Rules of Typography|last= Jury|first= David|year= 2004|publisher= Rotovision SA|location= Switzerland|isbn= 978-2-88046-798-2|at=159 pages |ref=Jur04}}
• {{cite web|url=http://www.rotovision.com/images/2880468221.pdf|title=What is Typography?|author=Jury, David|year=2009|publisher=Rotovision|access-date=9 October 2024|pages=28–87|ref=Jur09|archive-url=https://web.archive.org/web/20110715204643if_/http://www.rotovision.com/images/2880468221.pdf|archive-date=15 July 2011}}
• {{cite journal |last1= Kolers|first1= Paul A. |last2= Duchinsky|first2= Robert|last3= Ferguson|first3= Dennis C.|year= 1981|title= Eye Movement Measurement of Readability of CRT Displays|journal= Human Factors|volume= 23|issue= 5|pages= 517–527|ref=Kol81 |pmid= 7319497|doi= 10.1177/001872088102300502 |s2cid= 44651876 }}
• {{cite web|url= https://jkorpela.fi/unicode/guide.html|title= Guide to the Unicode Standard|author= Korpela, Jukka|date= 3 May 2005|work= Characters and Encodings|publisher= IT and Communication17 May 2010|ref= Kor05}}
• {{cite book |title= The Savvy Screenwriter: How to Sell Your Screenplay (and Yourself) Without Selling Out!|edition=Revised & Expanded|last= Kouguell|first= Susan|year= 2006|publisher= St. Martin's Griffin|location= New York|isbn= 978-0-312-35575-3|at=288 pages |ref= Kou06}}
• {{cite book |title= Guide to Legal Writing Style|edition= Fourth|last= LeClercq|first= Terri|year= 2007|publisher= Aspen Publishers|location= New York|isbn= 978-0-7355-6837-2|at= 144 pages |ref=LeC07}}
• {{cite web|url= http://www.aect.org/events/review/PropResults.asp?submit=View+Full+Proposal.&propid=148|title= The Effects of Computer-based Text Spacing on Reading Comprehension and Reading Rate|author= Leonard, Kristi|date= 10 October 2009|publisher= AECT1 February 2010|ref= Leo09|display-authors= etal|url-status= dead|archive-url= https://web.archive.org/web/20110717185321/http://www.aect.org/events/review/PropResults.asp?submit=View+Full+Proposal.&propid=148|archive-date= 17 July 2011}}
• {{cite book|title= Il Nuovo Manuale di Stile: Guida alla Redazione di Documenti, Relazioni, Articoli, Manuali, Tesi di Laurea|url= https://staticmy.zanichelli.it/catalogo/assets/a05.9788808118776.pdf|access-date= 15 May 2010|edition= 2.0|last= Lesina|first= Roberto|year= 2009|publisher= Zanichelli|language= it|ref= Les09}}
• {{cite book |title=The McGraw Hill Handbook of English Grammar and Usage|last1=Lester|first1= Mark|last2= Beason|first2=Larry|year= 2005|publisher= McGraw Hill|location=New York|isbn=978-0-07-144133-9|at=304 pages |ref=Les05}}
• {{cite web | url= http://spacewaste.wordpress.com/2009/08/06/wheres-the-evidence-to-justify-two-spaces/ | title= Where's the Evidence to Justify Two Spaces? | last1= Lloyd | first1= John Wills | last2= Hallahan | first2= Dan | date= 10 November 2009 | work= Spacewaste | publisher= Wordpress.com4 April 2010 | ref= Llo09 }}
• {{cite book |title=Webster's New World English Grammar Handbook|edition=2nd|last1=Loberger|first1=Gordon|last2=Shoup|first2=Kate|year=2009|publisher=Wiley Publishing|location=Hoboken, NJ|isbn=978-0-470-41080-6|at=408 pages |ref=Lob09}}
• {{cite book|last1=Loh|first1=Christian Sebastian|first2=Robert Maribe|last2=Branch|first3=Saun|last3=Shewanown|first4=Radwan|last4=Ali|title=IVLA Book of Selected Readings: Selected Readings of the IVLA Annual Conference|year=2002|publisher=IVLA|chapter=The Effect of Text Spacing After the Period on Time for On-Screen Reading Tasks|url=https://www.csloh.com/research/pdf/2002_IVLA.pdf|ref=Loh02}}
• {{cite book|title= Thinking with Type|url= https://archive.org/details/thinkingwithtype0000lupt|url-access= registration|author-link1= Ellen Lupton|last= Lupton|first= Ellen|year= 2004|publisher= Princeton Architectural Press|location= New York|isbn= 978-1-56898-448-3|at= [https://archive.org/details/thinkingwithtype0000lupt/page/n177 176]|ref= Lup04}}
• {{cite book |title=The Writing Digest Grammar Desk Reference|last1=Lutz|first1= Gary|last2= Stevenson|first2=Diane|year=2005|publisher=Writer's Digest Books|location=Cincinnati, OH|isbn=978-1-58297-335-7|ref=Lut05}}
• {{cite book |title= Web Style Guide|last1= Lynch|first1= Patrick J.|last2= Horton|first2= Sarah|year= 2008|publisher= Yale University Press|location= New Haven and London|isbn= 978-0-300-13737-8|at=352 pages |ref=Lyn08}}
• {{cite book |title= The American Printer: A Manual of Typography, Containing Practical Directions for Managing all Departments of a Printing Office, As Well as Complete Instructions for Apprentices: With Several Useful Tables, Numerous Schemes for Imposing Forms in Every Variety, Hints to Authors, Etc.|edition= Fifteenth – Revised and Enlarged|last= MacKellar|first= Thomas|year= 1885|publisher= MacKellar, Smiths & Jordan|location= Philadelphia|at=390 pages |ref=Mac85}}
• {{cite book |title=Linotype Keyboard Operation: Methods of Study and Procedures for Setting Various Kinds of Composition on the Linotype|author=Mergenthaler Linotype Company|year=1940|publisher=Mergenthaler Linotype Company|location=Brooklyn, N.Y|oclc=3230264|ref=Mer40}}
• {{cite web|url= https://www.microsoft.com/en-us/language/styleguides|title= Italian Style Guide: Microsoft Language Excellence|edition= 1.0|author= Microsoft|year= 2010|work= Microsoft Language Portal – Style Guide Download|publisher= Microsoft|language= it|access-date= 15 August 2021|ref= Mic10}}
• {{cite web|url= http://www.microsoft.com/typography/developers/fdsspec/spaces.aspx|title= Character design standards (5 of 10): Space Characters for Latin 1|author= Microsoft|work= Microsoft Typography|publisher= Microsoft|access-date= 16 May 2010|ref= MiR10|archive-url= https://web.archive.org/web/20100503134124/http://www.microsoft.com/typography/developers/fdsspec/spaces.aspx|archive-date= 3 May 2010|url-status= dead}}
• {{cite book |title= MHRA Style Guide: A Handbook for Authors, Editors, and Writers of Theses|last= Modern Humanities Research Association|year= 2002|publisher= Maney Publishing|location= Leeds, UK|isbn= 978-0-947623-62-3|at=92 pages |ref=Mod02}}
• {{cite web|url= http://www.mla.org/style_faq3|title= How many spaces should I leave after a period or other concluding mark of punctuation?|author= Modern Language Association|date= 15 January 2009|publisher= Modern Language Association31 January 2010|ref= MLA10|url-status= dead|archive-url= https://web.archive.org/web/20061012173129/http://www.mla.org/style_faq3|archive-date= 12 October 2006}}
• {{cite book |title=MLA Handbook for Writers of Research Papers|edition=7th|last=Modern Language Association|year=2009|publisher=Modern Language Association of America|isbn=978-1-60329-024-1|ref=MLA09}}
• {{cite journal|last1= Ni|first1= Xiaopeng|last2= Branch|first2= Robert Maribe|last3= Chen|first3= Kuan-Chung|last4= Clinton|first4= Gregory|editor1-first= Phillip J|editor1-last= Sleeman|year= 2009|title= The Effects of Text Spacing on Screen Reading Time and Comprehension|journal= International Journal of Instructional Media.|volume= 36|issue= 4|url= https://gwern.net/docs/design/typography/sentence-spacing/2009-ni.pdf|ref= Bra09}}
• {{cite journal |last1= North|first1= A. J.|last2= Jenkins|first2= L. B.|year= 1951|title= Reading Speed and Comprehension as a Function of Typography|journal= Journal of Applied Psychology|volume= 35|ref=Nor51|pmid=14861125 |issue= 4 |pages= 225–8 |doi=10.1037/h0063094}}
• {{cite journal |last= Osgood |first= Harry W. |year= 1919 |title= A Method for Teaching Straight Matter Composition |journal= Industrial-arts Magazine |volume= 8 |issue= 2 |pages= 47–48 |url= https://books.google.com/books?id=19pLAAAAYAAJ&pg=PA48 |access-date= 14 March 2013 |ref= Osg19 }}
• {{cite web |url= http://www.ritter.org.uk/H&C/H_edns/H_39e1983.html |title= Hart's Rules for Compositors and Readers at the University Press, Oxford |edition= Thirty-ninth |author= Oxford University Press |year= 1983 |publisher= Oxford Editorial |access-date= 24 May 2010 |ref= Har83 |archive-url= https://web.archive.org/web/20101130000917/http://www.ritter.org.uk/H%26C/H_edns/H_39e1983.html |archive-date= 30 November 2010 |url-status= usurped }}
• {{cite journal |last1= Payne|first1= Donald R.|year= 1967|title= Readability of Typewritten Material; Proportional Versus Standard Spacing|journal= The Journal of Typographic Research|volume= 1|issue= 2|pages= 125–136|ref=Pay67}}
• {{cite web | title= The Canadian Style Online | url= http://www.btb.termiumplus.gc.ca/tcdnstyl-chap?lang=eng&lettr=chapsect17&info0=17.07 | year= 2010 | publisher= Public Works and Government Services of Canada, The Translation Bureau, The Government of Canada's terminology and linguistic data bank TERMIUM-Plus | access-date= 26 April 2010 | ref= Pub10 }}
• {{cite web|url= http://publications.europa.eu/code/en/en-360400.htm|title= Interinstitutional Style Guide|author= Publications Office of the European Union|date= 24 July 2008|work= Europa|publisher= European Union12 May 2010|ref= Eur08}}
• {{cite web|url= http://buscon.rae.es/draeI/|title= Diccionario de la Lengua Española de la Real Academia Española|author= Real Academia Española|year= 2001|publisher= Real Academia Española|access-date= 20 April 2010|ref= Rea01}}
• {{cite web | url= http://www.webword.com/reports/period.html | title= One Versus Two Spaces After a Period | author= Rhodes, John S. | date= 13 April 1999 | work= Webword.com21 March 2010 | ref= Rho99 | url-status= dead | archive-url= https://web.archive.org/web/20100309110323/http://webword.com/reports/period.html | archive-date= 9 March 2010 }}
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• {{cite book|title= Formatting and Submitting your Manuscript|edition= 3rd|last1= Sambuchino|first1= Chuck|author2= ((The Editors of Writer's Digest Books))|year= 2009|publisher= Writer's Digest Books|location= Cincinnati, OH|isbn= 978-1-58297-571-9|at= 324|ref= Sam09|url= https://archive.org/details/formattingsubmit00samb|url-access= limited}}
• {{cite web|url=http://www.icee.usm.edu/icee/conferences/Conference%20Files/ASEE2002/P2002060INSTRSCA.PDF|title=Improving Instructional Materials by Improving Document Formatting|author=Scales, Alice Y.|year=2002|work=ASEE Southeast Section Conference|access-date=10 February 2010|ref=Sca02|archive-date=1 March 2012|archive-url=https://web.archive.org/web/20120301203613/http://www.icee.usm.edu/icee/conferences/Conference%20Files/ASEE2002/P2002060INSTRSCA.PDF|url-status=dead}}
• {{cite book |title= Dynamics in Document Design|last= Schriver|first= Karen A.|year= 1997|publisher= John Wiley & Sons|location= New York, Chichester, Brisbane, Toronto, Singapore, Weinheim|isbn= 978-0-471-30636-8|at=592 pages|ref= Sch97}}
• {{cite web|url= http://www.alistapart.com/articles/emen/|title= The Trouble With EM 'n EN (and Other Shady Characters)|author= Sheerin, Peter K.|date= 19 October 2001|work= A List Apart|publisher= A List Apart Magazine17 May 2010|ref= She01}}
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• {{cite web|url=http://www.executive-resumes.com/2009/07/dont-date-yourself-by-using-two-spaces.html|title=Don't Date Yourself by Using Two Spaces after a Period in Your Resume!|author=Smith, Laurie|date=8 July 2009|work=Executive Resumes and Career Transition Strategies: Reflections of an Executive Resume Writer|publisher=Creative Keystrokes Executive Resume Service30 March 2010|ref=Smi09|url-status=dead|archive-url=https://web.archive.org/web/20110710211507/http://www.executive-resumes.com/2009/07/dont-date-yourself-by-using-two-spaces.html|archive-date=10 July 2011}}
• {{cite book|title= Stop Stealing Sheep & Find Out How Type Works|author-link1= Erik Spiekermann|last1= Spiekermann|first1= Erik|last2= Ginger|first2= E.M.|year= 1993|publisher= Adobe Press|location= Mountain View, CA|isbn= 978-0-672-48543-5|ref= Spi93|url= https://archive.org/details/stopstealingshee00spie}}
• {{cite book |title= Getting it Right with Type|last1= Squire|first1= Victoria|last2= Willberg|first2= Hans Peter|last3= Forsmann|first3= Friedrich|year= 2006|publisher= Laurence King Publishing|location= London|isbn= 978-1-85669-474-2|at=176 pages |ref=Squ06}}
• {{cite book |title= The Pocket Idiot's Guide to Grammar and Punctuation: A Handy Reference to Resolve All Your Grammatical Problems|last= Stevenson|first=Jay|year=2005|publisher=Alpha Books|isbn=978-1-59257-393-6|at=208 pages |ref=Ste05}}
• {{cite book |title= The Blue Book of Grammar and Punctuation: An Easy-to-Use Guide with Clear Rules, Real-World Examples, and Reproducible Quizzes|edition=10th|last= Straus|first= Jane|year= 2009|publisher=Jossey-Bass|location= San Francisco, CA|isbn=978-0-470-22268-3|at=176 pages |ref=Str09}}
• {{cite web|url=http://www.itcfonts.com/Ulc/4111/DoubleSpaces.htm|title=Double Spaces Between Sentences ... Not!|author=Strizver, Ilene|work=U&lc: Upper and Lowercase Magazine Online: Issue 41.1.1|publisher=International Typeface Organization and Monotype Imaging|access-date=31 March 2010|ref=Str10|archive-url=https://web.archive.org/web/20100310192339/http://www.itcfonts.com/Ulc/4111/DoubleSpaces.htm|archive-date=10 March 2010|url-status=dead}}
• {{cite book |title= Type Rules: The Designer's Guide to Professional Typography|edition= 3rd|last= Strizver|first= Ilene|year= 2010|publisher= John Wiley & Sons|location= New Jersey|isbn= 978-0-470-54251-4|ref=Str11 }}
• {{cite book|title=The Grammar Bible|last1=Strumpf|first1=Michael|last2=Douglas|first2=Auriel|year=2004|publisher=Holt Paperbacks|location=New York|isbn=978-0-8050-7560-1|at=512|ref=Str04|url=https://archive.org/details/grammarbibleever0000stru|url-access=limited}}
• {{cite book|title= The Elements of Style|edition= 50th Anniversary|last1= Strunk|first1= William|author-link1= William Strunk|last2= White|first2= E.B.|year= 2008|publisher= Longman|isbn= 978-0-205-63264-0|at= 128|ref= Str08|url= https://archive.org/details/elementsofstyle00stru_0|url-access= limited}}
• {{cite book |title=Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers |edition=7 |author=Style Manual Committee |year=2006 |publisher=Council of Science Editors |location=Reston, VA |at=[https://archive.org/details/scientificstylef0000unse/page/658 658 pages] |isbn=978-0-9779665-0-9 |ref=CSE06 |url=https://archive.org/details/scientificstylef0000unse/page/658 }}
• {{cite book |title= My Grammar and I: Or Should that be "Me"?|last= Taggart|first= Caroline|year=2009|publisher=JA Wines|location= London|isbn=978-1-60652-026-0|ref=Tag09}}
• {{cite book |title= Legibility of Print|author-link1= Miles Tinker|last=Tinker|first=Miles A.|year= 1963|publisher= Iowa State University Press|location= Iowa|isbn= 978-0-8138-2450-5|ref=Tin63}}
• {{cite journal |last= Tinker|first= Miles A.|date=Summer 1966|title= Experimental Studies on the Legibility of Print: An Annotated Bibliography|journal= Reading Research Quarterly|volume= 1|issue= 4|pages= 67–118|jstor= 747222|ref=Tin10}}
• {{cite book|title= The Screenwriter's Bible: A Complete Guide to Writing, Formatting, and Selling Your Script|edition= 4th|last= Trottier|first= David|year= 2005|publisher= Silman James Press|location= Los Angeles|isbn= 978-1-879505-84-1|ref= Tro05|url= https://archive.org/details/screenwritersbib00trot_0}}
• {{cite book|title= Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation|url= https://archive.org/details/eatsshootsleave00trus|url-access= limited|author-link1= Lynn Truss|last= Truss|first= Lynn|year= 2004|publisher= Gotham Books|location= New York|isbn= 978-1-59240-087-4|page= [https://archive.org/details/eatsshootsleave00trus/page/25 25]|ref= Tru04}}
• {{cite book|title= A Manual for Writers of Research Papers, Theses, and Dissertations|edition= 7th|author-link1= Kate Turabian|last= Turabian|first= Kate L.|editor1-first= Wayne C.|editor1-last= Booth|editor2-first= Gregory G.|editor2-last= Colomb|editor3-first= Joseph M.|editor3-last= Williams|year= 2007|publisher= University of Chicago Press|location= Chicago|isbn= 978-0-226-82337-9|ref= Tur07|url= https://archive.org/details/manualforwriters00kate}}
• {{cite web |url= https://www.unicode.org/reports/tr14/ |title= Unicode Standard Annex #14: Unicode Line Breaking Algorithm |author= Unicode |year= 2009 |work= Unicode Technical Reports |publisher= Unicode |access-date= 17 May 2010 |ref= Uni09 }}
• {{cite web |url=http://www.gpoaccess.gov/stylemanual/ |title=U.S. Government Printing Office Style Manual |last=United States. |date=16 September 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080831023726/http://www.gpoaccess.gov/stylemanual/ |archive-date=31 August 2008 }}
• {{cite web|url=http://www.navy.mil/tools/view_styleguide_all.asp|archive-url=https://web.archive.org/web/20041124084708/http://www.navy.mil/tools/view_styleguide_all.asp|url-status=dead|archive-date=24 November 2004|title=U.S. Navy Style Guide "Punctuation"|publisher=United States Navy|access-date=17 January 2010}}
• {{cite book|title= Manual of Style: A Compilation of Typographical Rules Governing the Publications of the University of Chicago, with Specimens of Types Used at the University Press|url= https://archive.org/details/manualstyleacom01presgoog|edition= Third|author= University of Chicago Press|author-link= University of Chicago Press|year= 1911|publisher= University of Chicago|location= Chicago|ref= Chi11|isbn= 978-1-145-26446-5}}
• {{cite book|title= The Chicago Manual of Style: For Authors, Editors, and Copywriters|edition= 12th Revised|author= University of Chicago Press|author-link= University of Chicago Press|year= 1969|publisher= University of Chicago Press|location= Chicago and London|quote= Library of Congress Catalog Card Number: 6-40582|ref= Chi69|isbn= 978-0-226-77008-6|url= https://archive.org/details/manualofstylefor00univ}}
• {{cite book|title= The Chicago Manual of Style: The Essential Guide for Writers, Editors, and Publishers|edition= 15th|last= University of Chicago Press|author-link= University of Chicago Press|year= 2003|publisher= University of Chicago Press|location= Chicago and London|isbn= 978-0-226-10403-4|ref= Chi03|url= https://archive.org/details/chicagomanualofs00univ_0}}
• {{cite web|url=http://www.chicagomanualofstyle.org/CMS_FAQ/OneSpaceorTwo/OneSpaceorTwo03.html|title=One Space or Two?|work=Chicago Manual of Style Online|publisher=University of Chicago Press|author-link=University of Chicago Press|year=2007|access-date=8 February 2010|at=984 pages|ref=Chi07}}
• {{cite book |title= The Chicago Manual of Style: The Essential Guide for Writers, Editors, and Publishers|edition= 16th|last= University of Chicago Press|author-link= University of Chicago Press|year= 2010|publisher= University of Chicago Press|location= Chicago and London|isbn= 978-0-226-10420-1|ref= Chi10}}
• {{cite book|title= The Elephants of Style: A Trunkload of Tips on the Big Issues and Gray Areas of Contemporary American English|last= Walsh|first= Bill|year= 2004|publisher= McGraw Hill|location= New York|isbn= 978-0-07-142268-0|at= [https://archive.org/details/elephantsofstyle00wals/page/238 238 pages]|ref= Wal04|url= https://archive.org/details/elephantsofstyle00wals/page/238}}
• {{cite web|url= http://www.w3.org/TR/html4/struct/text.html|title= 9.1 White Space|author= W3C|date= 24 December 1999|work= HTML 4.01 Coding Specification|publisher= W3C17 May 2010|ref= WC399}}
• {{cite web|url= http://www.w3.org/TR/html4/struct/text.html|title= 24.4 Character Entity References for Markup-Significant and Internationalization characters|author= W3C|date= 24 December 1999|work= HTML 4.01 Coding Specification|publisher= W3C17 May 2010|ref= WC499}}
• {{cite web|url= http://blog.apastyle.org/apastyle/2009/07/on-two-spaces-following-a-period.html|title= On Two Spaces Following a Period|author= Weiderkehr, Sarah|date= 30 July 2009|publisher= American Psychological Association29 January 2010|ref= Wei09}}
• {{cite book|title= The Iron Whim: A Fragmented History of Typewriting|last= Wershler-Henry|first= Darren|year= 2005|publisher= Cornell University Press|location= Ithaca and London|isbn= 978-0-8014-4586-6|ref= Wer05|url= https://archive.org/details/ironwhim00wers}}
• {{cite book|title= Type and Layout: How Typography and Design Can Get your Message Across – Or Get in the Way|last= Wheildon|first= Colin|year= 1995|publisher= Strathmoor Press|location= Berkeley|isbn= 978-0-9624891-5-0|at= [https://archive.org/details/typelayouthowtyp0000whei/page/248 248 pages]|ref= Whe95|url= https://archive.org/details/typelayouthowtyp0000whei/page/248}}
• {{cite web|url= http://widespacer.blogspot.com/2014/03/one-or-two-spaces-after-period-how.html|title= One or two spaces after a period? How about three?|author= Wide Spacer|year= 2014|work= Wide Spacer blog|access-date= 19 March 2014|ref= Wid14}}
• {{cite book |title= Style Manual: For Authors, Editors and Printers|edition= 6th|author= Wiley, John, & Sons Australia|year= 2007|publisher= John Wiley & Sons Australia|isbn= 978-0-7016-3648-7|ref=Wil07}}
• {{cite book|title= The PC is Not a Typewriter|edition= 1st|last1= Williams|first1= Robin|year= 1995|publisher= Peachpit Press|location= Berkeley, CA|isbn= 978-0-938151-49-4|at= [https://archive.org/details/pcisnottypewrite00will/page/n97 96]|ref= Wil95|url= https://archive.org/details/pcisnottypewrite00will|url-access= limited}}
• {{cite web|url= https://www.adobe.com/products/adobemag/archive/pdfs/9507lsrw.pdf|title= Thirteen Telltale Signs|author= Williams, Robin|date= July–August 1995|work= Adobe Magazine|publisher= Adobe|access-date= 10 February 2010|ref= Will95|url-status= dead|archive-url= https://web.archive.org/web/20101203230205/http://www.adobe.com/products/adobemag/archive/pdfs/9507lsrw.pdf|archive-date= 3 December 2010}}
• {{cite book |title= The Mac is Not a Typewriter: A Style Manual for Creating Professional-level Type on Your Macintosh|edition= 2nd|last1= Williams|first1= Robin|year= 2003|publisher= Peachpit Press|location= Berkeley, CA|isbn= 978-0-201-78263-9|at=96 pages |ref= Wil03}}

{{refend}}

• {{cite web|url= http://www.writersblock.ca/tips/monthtip/tipmay97.htm|title= Writing Tips: Spacing (1)|date= May 2009|work= Writer's Block|publisher= NIVA Inc|issn= 1488-4801|url-status= dead|archive-url= https://web.archive.org/web/20071016043217/http://www.writersblock.ca/tips/monthtip/tipmay97.htm|archive-date= 16 October 2007}}
• {{cite web|url= http://www.writersblock.ca/tips/monthtip/tipjun97.htm|title= Writing Tips: Spacing (2)|date= June 2009|work= Writer's Block|publisher= NIVA Inc|issn= 1488-4801|url-status= dead|archive-url= https://web.archive.org/web/20071016044654/http://www.writersblock.ca/tips/monthtip/tipjun97.htm|archive-date= 16 October 2007}}

• {{cite web |url=http://www.slate.com/id/2281146/ |title=Space Invaders: Why You Should Never, Ever Use Two Spaces After a Period |author=Manjoo |first=Farhad |date=13 January 2011 |work=Slate}}
• {{cite web |url=https://www.theatlantic.com/culture/archive/2011/01/you-can-have-my-double-space-when-you-pry-it-from-my-cold-dead-hands/69592/ |title=You Can Have My Double Space When You Pry it From My Cold, Dead Hands |author=McArdle |first=Megan |date=14 January 2011 |work=The Atlantic}}
• {{cite web |url=http://mentalfloss.com/article/52994/how-many-spaces-should-there-be-end-sentence/ |title=How Many Spaces Should There Be at the End of a Sentence? |author=Okrent |first=Arika |date=2 October 2013 |website=Mental Floss |publisher=}}
• {{cite web |url=http://www.webword.com/reports/period.html |title=One Versus Two Spaces After a Period |author=Rhodes |first=John S. |date=13 May 1999 |work=WebWord.com |url-status=dead |archive-url=https://web.archive.org/web/20100309110323/http://webword.com/reports/period.html |archive-date=9 March 2010}}
• {{cite web|url= http://www.typophile.com/node/3466|author= Typophile|title= Double-spacing After Periods|year= 2011|work= Typophile|publisher= Punchcut|url-status= dead|archive-url= https://web.archive.org/web/20071210174623/http://typophile.com/node/3466|archive-date= 10 December 2007}}
• {{cite web |url=http://www.ditchwalk.com/2011/01/19/two-spaces-after-a-period/ |author=Barrett |first=Mark |title=Two Spaces After a Period |date=19 January 2011 |work=Typophile |publisher=Ditchwalk}}

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Category:Punctuation

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