Wikipedia:Manual of Style (footnotes)
| This guideline is a part of the English Wikipedia's Manual of Style. Use common sense in applying it; it will have occasional exceptions. Please ensure that any edits to this page reflect consensus. |
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Wikipedia footnotes serve two purposes. First, to add explanatory material, particularly if the added information would be distracting if written out in the main article. Second, they are used to present citations to reliable sources that support assertions in the main article.[1] As explained at Wikipedia:Citing sources, footnoting is one of several alternative ways to present citations.
Wikipedia has several mechanisms for creating footnotes that contain reciprocal hyperlinks, so that clicking on a number or symbol found in the main text brings readers to the corresponding footnote, and vice versa. Thus, as described below, two different types of footnote markup may be used to distinguish explanatory footnotes from citation footnotes. See, for example, the Jane Austen article.
The prevailing system for adding footnotes to an article is Cite.php, which involves the <ref> tag. This system has several advantages, including automatic sequential numbering of the footnotes and provisions for multiple references to the same footnote. To add such a footnote to an article, the editor includes the text of the footnote between two HTML-style tags (e.g., <ref>Text of footnote goes here.</ref>). Different classes of footnotes can be defined within an article using the group parameter inside the ref tag, as described below.
Editors may also use the older system of template-based footnotes, such as {{ref label}} and {{note label}}. These have the disadvantage that they are not numbered automatically; the editor has to choose a specific label. It is generally expected that footnotes will be labeled in the order in which they occur in the text. Therefore, if an editor adds such a template-based footnote in the middle of an article, the editor should also renumber/increment all the subsequent footnotes of the same type, by hand.
| How to use |
- A simplified explanation is given at Help:Footnotes
- Place a <ref> ... </ref> opening and closing tag where you want a footnote reference number to appear in an article—type the text of the note between the ref tags.
- Place the <references /> tag or {{Reflist}} tag in either a "Notes" or "References" section as explained in the Guide to Layout — the list of notes will be generated in that section.
This page itself uses footnotes, such as the one at the end of this sentence.[2] If you view the Wikicode of this page by clicking "Edit this page", you can see a working example of footnotes.
[edit] Listing footnotes at the end of the article: using <references /> or {{Reflist}}
If you are creating a new article or editing an article that does not have footnotes already and you wish to add footnotes to the article, you must create a new section towards the end of the article (usually titled "Notes" or "References", see Layout) and place one of these in it: <references /> or {{Reflist}}.
{{Reflist}} displays the footnotes in a smaller font in the old monobook skin.
{{Reflist|2}} is used to split long listings into a specific number of columns. Three-column lists (and larger) are inaccessible to users with smaller/laptop monitors and should be avoided unless they are supporting shortened footnotes.
To prevent display problems with multi-column formats on smaller monitors, the "colwidth" parameter can be used with {{Reflist}} to specify a fixed column width. The number of columns displayed will then automatically adjust to match the size of the user's browser window. For example, {{Reflist|colwidth=20em}} will display as many columns with a minimum width of 20 ems as will fit in the browser window.
Multi-column lists are not currently supported by Internet Explorer or Safari.
Two of the above options are included in the "markup" below the edit box; if you click on this, it will add it to the page. Once you save your edit, footnotes will be automatically generated in the new references section.
[edit] Reference name (naming a ref tag so it can be used more than once)
| Shortcut: WP:REFNAME |
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To give a footnote a unique identifier, use <ref name="name"> ... </ref>. You can then refer to the same footnote again by using a ref tag with the same name like <ref name="name" />. The name cannot be a number, or the extension will return an error. The ref name need not be placed within quotes unless it contains a space, certain punctuation marks, or non-ASCII characters[3] (the wiki parser converts single word quoteless attribute values into validly quoted XHTML). Note that any quotation marks placed around the ref name must be straight quotes (") rather than curly quotes (“ or ”).
Named references are used when there are several cases of repetition of exactly the same reference, including the page number for books; they should not be used to cite different pages in the same book. Named references in wikitext serve a purpose similar to loc. cit., ibid., Id. or supra in printed media. See also cautions in Style below.
Only the first occurrence of text in a named ref will be used, although that occurrence may be located anywhere in the article. You can either copy the whole footnote, or you can use a terminated empty ref tag that looks like this: <ref name="name" />. Such forward-slash-terminated named tags may precede the definition of the named reference.[4] When using named references, the use of <ref name="name" /> for the later instances of the named footnote is encouraged, rather than copying the whole footnote again. Whole footnotes tend to reduce the readability of the article's text in edit mode, which makes finding specific parts of the text when editing tedious.
This, like the use of named footnotes in the first place, is a matter for editorial judgment; some editors do repeat the entire footnote, in case rearrangement of the text removes the first note, or places it after a blank note (previously, the note had to be defined prior to use, although that is no longer the case). If so, all instances of the footnote must be updated together, which can be more trouble than it saves.
In the following example, the same source is cited three times.
This is an example of multiple references to the same footnote.<ref name="multiple" /> Such references are particularly useful when citing sources where different statements come from the same source.<ref name="multiple">Author, A. (2007). "How to cite references", New York: McGraw-Hill.</ref> A concise way to make multiple references is to use empty ref tags, which have a slash at the end.<ref name="multiple">This text is superfluous, and won't show up anywhere. We may as well just use an empty tag.</ref>
== Notes ==
{{reflist}}
The edit text above gives the following result in the article:
This is an example of multiple references to the same footnote.[1] Such references are particularly useful when citing sources where different statements come from the same source.[1] A concise way to make multiple references is to use empty ref tags, which have a slash at the end.[1]
Notes
One should be particularly careful when deleting a named reference with text content, because the footnote text will be deleted unless it is copied to another ref tag with the same name.
[edit] Citation templates
Text placed between <ref> and </ref> may be short notes or full bibliographic references, and may be formatted either by hand or with the assistance of templates. Instructions on available templates to help format bibliographic references may be found at Wikipedia:Citation templates. Use of such templates is neither encouraged nor discouraged; see WP:CITE.
[edit] Previewing a single section edit
[edit] Notes and references not normally visible
When you edit a single section on a long page, the Notes or References section will not be visible when you preview your edits unless you use the editor gadget wikEd. Thus you ordinarily cannot see how your footnotes (text you place between <ref> and </ref> tags) will later appear when you save your edits.
[edit] Workaround for notes and references
A simple workaround is to temporarily insert a <references /> or {{Reflist}} tag at the bottom of the edit box of the section you are editing (wikEd does this automatically). Your footnotes will appear at the bottom of your section so you can preview them. When you are satisfied with your edits to the section, delete your temporary <references /> or {{Reflist}} tag, and save your edits. Now your footnotes should appear in the "Notes" or "References" section along with other footnotes on the page.
While you preview the footnotes in a section this way, the first footnote in the section will temporarily have a number of one (1), because the preview will not show footnotes from elsewhere on the page. The footnotes will renumber properly across the entire article after you save your edited section.
[edit] Re-use of reference(s) from another section
Another complication is that you will not be able to preview the effect of citing a footnote from another section merely by citing its name (for example: <ref name="multiple" />). If the section you want to edit reuses footnotes from elsewhere on the page, a simple solution is to edit the whole page at once in order to preview the footnotes accurately.
If you want to avoid this, the only workaround would be to copy and temporarily insert the full code of the relevant reference(s) at the top of the edit box of the section you are editing. If you have used the "workaround for notes and references" (above) the footnotes will appear at the bottom of your section so you can preview them. When you are satisfied with your edits to the section, delete the temporary full reference code and save your edits. Now your footnotes should appear in the "Notes" or "References" section along with other footnotes on the page.
[edit] Newline after closing ref tag
| Shortcut: WP:NEWREF |
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Reading inline <ref> tags can be difficult in edit mode, particularly where ref tags contain large amounts of reference text, such that simply discerning where the reference ends and the article text begins can be time-consuming.
As a convenience, it may be helpful to carriage return (newline) the article text that comes just after the closing </ref> tag, such as:
Article text text <ref name="refname"> Reference text... </ref> {return}
→continuing text text text..
This allows editors to see clearly where the ref tag body ends and the article text begins, and it doesn't alter the way the text appears in the output view mode —text sections need to be separated by two newline/carriage returns to be formatted as separate paragraphs.
[edit] Errors and bugs
The Cite.php extension includes extensive error checking. Error messages begin with Cite error: and include a link to a help page.
[edit] Known bugs
- Internal links and wiki formatting work as normal within the text of the citation, like this: <ref>''[[Wikipedia]]'', 18 March 2007.</ref> However, the "pipe trick" will not expand a link for you in ref text; you must type out [[George Clark (historian)|George Clark]], rather than just typing [[George Clark (historian)|]] and letting the software fill in the text after the pipe. See Help:Pipe trick#Cite.php footnotes and the pipe trick.
- When citing a website within the ref tags, include a name for the site inside the brackets for the URL. Unnamed URLs appear as numbers, so <ref>[http://www.google.com]</ref> results in the footnote being displayed as [1]; the reader clicks to the numbered footnote only to see another number. Thus, use a name in the link to display the website page title in the reference list, as in this example: <ref>[http://www.google.com Google]</ref>.
- Avoid use of "subst", or at least verify that it works correctly. A MediaWiki bug (Bugzilla:2700) prevents the expansion of certain (if not all) "subst"'s within refs.
- Reading inline <ref> tags can be difficult in edit mode (see #Newline after closing ref tag).
| Style |
[edit] Ref tags and punctuation
| Shortcuts: WP:REFPUN WP:REFPUNC WP:REFPUNCT |
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Material may be referenced mid-sentence or at the end of a sentence or paragraph. When a reference tag coincides with punctuation, the reference tag is normally placed immediately after the punctuation, except for dashes, as recommended by the Chicago Manual of Style and other style guides.[5][6] Some editors prefer the in-house style of journals such as Nature, which place references before punctuation. If an article has evolved using predominantly one style of ref tag placement, the whole article should conform to that style unless there is a consensus to change it.
[edit] Style recommendations
- Do not use ibid., Id., or similar abbreviations in footnotes. Other editors who add new references to the article may not take the time to correct Ibid references broken by their addition (op. cit. is less problematic in that it should refer explicitly to a citation contained in the article). However, not all readers are familiar with the meaning of the terms. If a reference is reused in more than one footnote, it is preferable to use the format "Smith, Short Title, 182" rather than "Ibid, 182", so as to avoid these problems, or use named references if appropriate.
- Consider maintaining a separate bibliography/references section that gives full publication details for frequently cited sources, then you only need to cite the author, short title or year of publication, and page number in specific notes, following shortened footnotes. For examples of this usage, see Johannes Kepler and Rabindranath Tagore.
- The decision on whether to use quotes in footnotes is primarily a decision of style and may vary from article to article. Some citation templates include parameters for quotes, and quoted text can also be added inside a footnote either preceding or following a template-produced citation. Quoting text can be useful for the verifiability of material in an article. Footnoted quotes are acceptable if they are brief, relevant to the article text that is being footnoted, compliant to copyright (including fair use where applicable), of use or interest to the reader, and not used as an evasion of other guidance (most notably: content policy).[7] Where there is disagreement on the use of quotations in footnotes on a particular article, consensus should be sought on the talk page for that article.
| Size and display |
[edit] Resizing references
| Shortcut: WP:REFSIZE |
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Some editors prefer references to be in a smaller font size than the text in the body of the article. Although smaller text has some disadvantages, it is common when there is a long list of references (as a rule of thumb, at least ten) to replace the basic <references /> tag with {{Reflist}}, which reduces the text size to 90%. (Note: Do not use {{Reflist}} with a "subst:".) The underlying CSS class is "references-small", so an alternative is to use this directly: <div class="references-small"><references /></div>. If this class is used to make other sections at the bottom of the page ("Notes", "See also", "External links", etc.) small for consistency (this is rarely done), the div tags must be opened and closed within each section.
[edit] Multiple columns
Footnotes can be formatted in columns by using {{Reflist|number of columns}}. See the template documentation for browser support issues.
Using a set number of columns may make text too narrow when displayed with large fonts or small screens. Using {{Reflist|colwidth=30em}} will allow the browser to automatically choose the number of columns based on the font size selected by the user and width of the web browser. Choose a column width that is appropriate for the average width of the references on the page.
Multicolumn display can be disabled for your account by customizing your personal CSS file. (See {{Reflist}})
[edit] Avoid scrolling lists
As explained in more detail at WP:Citing sources, scrolling lists of references should never be used because of issues with readability, accessibility, printing, site mirroring, and display.
| Advanced |
[edit] Separating reference lists and explanatory notes
| Shortcuts: WP:REFGROUP WP:REFNOTE |
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It may be desirable for an article to list sources separately from explanatory notes. When this is done the sources may appear in an alphabetized list unlinked to the article (e.g., Starship Troopers) or in a list that is linked to specific text in the article by footnotes (e.g., Jane Austen).[8] A separate section containing references is usually given the title "References", while the explanatory notes section retains the "Notes" title.
One way to generate a linked list of sources involves the group= option of the <ref> tag, which is analogous to the name= option described above. In this approach, narrative references are given their own "group" namespace. The group identifier is specified inside explanatory note <ref> tags and its final <references /> tag. The closing tag </ref> does not change.
For example:
Claim A<ref group="nb">Claim A explained.</ref>
Claim B<ref group="nb" name="ex02">Claims B and D explained.</ref>
Claim C<ref>Claim C referenced.</ref>
Claim D<ref group="nb" name="ex02"/>
Claim E{{#tag:ref|Claim E explained.<ref>Nested reference for explanation of claim E.</ref>|group="nb"}}
== Notes ==
<references group="nb" />
== References ==
Rendering:
It is also possible to use the reference templates, e.g., {{ref label}} and {{note label}} to separate a sources list from content notes. As with all citation styles, consensus should be achieved on the talk page before implementing such a change.
[edit] Nesting references: citations within explanatory notes
| Shortcut: WP:REFNEST |
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Explanatory notes may need to be referenced. Due to limitations in the Cite.php software, reference tags cannot be nested; that is a set of <ref></ref> tags cannot be placed inside another pair of <ref></ref> tags; attempting to do so will result in a cite error.
The magic word {{#tag:ref}} may be used to nest references. The markup is:
{{#tag:ref|refcontent|name=name|group=groupname}}
where refcontent may include <ref></ref> tags. The name and groupname are optional, but must come after refcontent. A named #tag:ref construct may be reused by invoking:
<ref name=name group=groupname/>
Attempting to use #tag:ref more than once within list-defined references will result in a cite error; see bug 20707http://bugzilla.wikimedia.org/show_bug.cgi?id=20707.
[edit] List-defined references
| Shortcut: WP:LDR |
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As of September 2009, references may be defined within <references> </references> markup or with {{reflist}} using |refs= and invoked within the content. This can help separate large reftags with long cite entries from the ordinary text, making it easier to read and to edit.
An example (uses a group just to separate it from other examples):
The quick brown fox jumps over the lazy dog.<ref name="LazyDog" group="Ref"/> Amazingly few discotheques provide jukeboxes.<ref name="Jukeboxes" group="Ref"/> How razorback-jumping frogs can level six piqued gymnasts.<ref name="JumpingFrogs" group="Ref"/> <references group="Ref"> <ref name="LazyDog">This is the lazy dog reference.</ref> <ref name="Jukeboxes">This is the jukeboxes reference.</ref> <ref name="JumpingFrogs">This is the jumping frogs reference.</ref> </references>
The quick brown fox jumps over the lazy dog.[Ref 1] Amazingly few discotheques provide jukeboxes.[Ref 2] How razorback-jumping frogs can level six piqued gymnasts.[Ref 3]
List defined references can also be implemented using a {{reflist|refs=}} template. Any blank lines placed between the citations in a reflist will make no difference to the download size or output format of an article. Thus, for ease of editing and article maintenance, it can be helpful to separate the citations using a blank line between each cite.
Another example (uses a second group to separate it from other examples):
Rats live on no evil star.<ref name="Rats" group="Ref2"/>
Mountains rarely visit religious leaders.<ref name="Mountains" group="Ref2"/>
The man on the flying trapeze does not have life insurance.<ref name="Trapeze" group="Ref2"/>
{{reflist|group="Ref2"|refs=
<ref name="Rats">This is the rats reference.</ref>
<ref name="Mountains">This is the mountains reference.</ref>
<ref name="Trapeze">This is the flying trapeze reference.</ref>
}}
Rats live on no evil star.[Ref2 1] Mountains rarely visit religious leaders.[Ref2 2] The man on the flying trapeze does not have life insurance.[Ref2 3]
Defined references must be used within the body; unused references will show an error message. The references will appear numbered in the order that they are referred to in the text, regardless of how they are ordered within the reflist/references template. For an article which may have many references it's a good idea to name and sort the references in an orderly way for editing purposes. One way is to follow the Harvard style, like name = "Author_Date_Publisher" on the form "AuthorLastName_YYYY-MM-DD_Publisher" and sort the references on this key.
| Caution on converting citation styles |
An older system using {{ref}} and {{note}} templates is still common. Converting this older system[12] to the new <ref>...</ref> system can make the references in an article easier to maintain.
Converting citation styles should not be done without first gaining consensus for the change on the article's talk page.
A December 2005 ArbCom case ruled that the following scripts could no longer be used by a certain Wikipedian:
- Wikipedia:Footnote3/numlink2note.pl, explained at Wikipedia talk:Footnote3/numlink2note.pl
- Wikipedia:Footnote3/order-footnote.pl, explained at Wikipedia talk:Footnote3/order-footnote.pl
Similarly, individual users may be forbidden to "manually convert citation styles on any articles."
So, tread lightly, and seek consensus first, before converting citation styles. For example, when using (semi-)bot tools as listed below:
- User:Cyde/Ref converter converts articles that use the {{ref}} and {{note}} system into the more recent mw:Extension:Cite/Cite.php system;
- Citation Tool diagnoses and fixes sequencing and duplication errors in Cite.php references. In the future, Citation Tool may (optionally) enable user-guided conversion of some or all of the <ref>-numbered citations to named notes using the footnote3 template technology (which includes Harvard references).
CAUTION: do not edit-war with automated tools that convert in opposing directions.
| Compatibility with other MediaWiki sites |
As of late December 2005, the mw:Extension:Cite/Cite.php extension to MediaWiki has been installed on all Wikimedia wikis. Other wikis that use the MediaWiki software may not have this extension installed, and therefore may be unable to display Cite.php footnotes. The Special:Version page on any MediaWiki wiki shows the installed extensions.
Extensions like Cite/Cite.php are installed after installing MediaWiki software; these extension files are placed in the directory wiki/extensions/.
| See also |
- Wikipedia:Verifiability, the relevant policy regarding what material should be cited
- Wikipedia:Citing sources, the relevant style guide.
- Wikipedia:Citing sources/example style, listing also several examples of non-numbered APA style and Harvard referencing techniques
- Wikipedia:Template messages/Sources of articles for complete list of templates that are available for citations; note that several of these templates can easily be combined with "footnote3" footnotes, see Gymnopédie#Notes and references for an example.
- Wikipedia:WikiProject Wikicite: Proposal for use of database of citations.
- Wikipedia:WikiProject Fact and Reference Check
- Other types of numbered footnotes:
- Wikipedia:Footnote1, a very old, manually numbered footnote system that should not be used.
- Wikipedia:Footnote2, another obsolete system that should not be used.
- Wikipedia:Footnote3, an automatically numbered footnote system using templates, which is widely used but has been replaced by MediaWiki footnotes.
- Help:Footnotes
- mw:Extension:Cite/Cite.php (formerly at meta:Cite.php) – description of the <ref>...</ref>/<references /> system at metawiki
- meta:Biblio – Biblio.php, an extension of Mediawiki which provides a citation manager. (beta maturity)
- Bug 2745: Have References text edit window on Edit pages.
- Template:Rp – adds ability to handle Harvard-style page number citations to Cite.php inline references (intended for use when one source is cited a large number of times, and would produce either too many individual entries under <references /> for the same source, or one exceedingly long entry that cited too many pages to possibly be useful to readers).
- m:Wikicite an idea for standardizing how facts are cited.
- m:Wikicat is the bibliographic catalog used by the WikiTextrose project.
- m:WikiTextrose, a text relationship database for mapping the various interactions between interpretable artifacts.
- Wikipedia:Referencing for beginners A simple practical guide to getting started.
| Notes |
- ^ Citing sources is important for improving the quality of Wikipedia's articles. A key content policy, Wikipedia:Verifiability, says that any material that is challenged or likely to be challenged, including any contentious material about living people and all quotations, must have a source. Unsourced or poorly sourced material may be removed from any article, and if it is, the burden of proof is on the editor who wishes to restore it.
- ^ This footnote is used as an example in the "How to use" section.
- ^ Specifically, quotes are not necessary if the name contains only printable ASCII characters excluding space, straight double quote ("), dollar sign ($), percent sign (%), straight single quote ('), plus sign (+), equals sign (=), backslash (\), and the greater-than sign (>). With quotes, the only restriction is that the name may not contain the less-than sign (<) or the quote character.
- ^ Wikipedia Signpost. November 13, 2006.
- ^ The Chicago Manual of Style, 14th ed. 1993, Clause 15.8, p. 494 - "The superior numerals used for note reference numbers in the text should follow any punctuation marks except the dash, which they precede. The numbers should also be placed outside closing parentheses." - See also CMoS Online, Style Q&A, Punctuation, cited 19 February 2010.
- ^ Other style guides suggesting that superscript note reference numbers should generally be placed after punctuation include: Oxford/Hart's Rules, the MLA Style Manual, APA Style, Dictionary.com, IEEE style and Legal Blue Book Style (as well as the general exception for dashes, guides may variously make other exceptions for colons, semicolons and quotation marks).
- ^ For example, to work around the proscription placed on editors by Wikipedia:Neutral point of view#Attributing and substantiating biased statements.
- ^ See Wikipedia:Citing sources for more information about alternative ways to present citations.
- ^ The Wikipedia:Footnote3 system created footnotes with the {{ref}}/{{note}} and the {{ref_label}}/{{note_label}} pairs of templates. The system may be encountered on many Wikipedia pages.
- This example footnote was not created with <ref> ... </ref> Additional footnotes that follow a <references/> which do not continue the numbering are mistakes; they should be corrected by converting them to footnotes using "ref" tags. If they are not true references, they can be put in a separate section; see Wikipedia:Layout for some commonly used possibilities.