Help:Footnotes
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This page explains how to create Footnotes in articles. In this context, Footnotes are a Wikipedia specific manner of including sources and should not be confused with the general concept of footnotes. This how-to does not cover the formatting of citations.
Footnotes are used most commonly to provide references (bibliographic citations) to reliable sources in articles, explanatory information, and source information for tables and other elements. The use of Footnotes is not required by any policy or guideline, and other systems of inline citation, including Shortened footnotes and Parenthetical referencing, may be used at the editors' discretion in accordance with the guideline on variation in citation methods.
Only certain types of material on the English Wikipedia are required to have an inline citation to a reliable source. There is no requirement to provide a citation for every sentence, because multiple sentences may be supported by the same footnote. For advice on which material should be cited, see the guidelines on when you must use inline citations, the good article criteria and when to cite. For advice on how to organize and format bibliographic citations to reliable sources, see the guideline on citing sources and examples of citation templates.
Footnotes are created using the Cite software extension. This extension adds the HTML-like elements <ref>...</ref>, <references /> and <references>...</references>. The elements are also used in a number of templates; for example, it is becoming more common to use {{reflist}} rather than <references /> as it can style the reference list.
Overview
The Footnotes system shows two elements on the page:
- Footnote markers show in the content as a superscripted footnote label enclosed in brackets. The footnote label shows as a number, letter or word. The footnote label is linked to the full footnote with a matching label. Examples: [1] [a] [Note 1]. Clinking on the footnote marker jumps to the footnote and highlights the citation.
- A Footnote contains the full citation and shows in a list wherever the reference list markup is placed. Footnotes are formatted in an ordered reference list with each entry starting with the footnote label in plain text. The entire reference list is formatted in a slightly smaller font.
- Each successive footnote label is automatically incremented. Thus the first footnote marker would be [1], the second would be [2] and so on. Custom labels are also incremented: [a][b][c], [Note 1] [Note 2] [Note 3].
- For a single use footnote, the label is followed by a caret (^) that is a backlink to the matching footnote marker. For example:
- If a named footnote is used in the text multiple times, then the footnote has multiple backlinks shown as letters:
- Clicking on the backlink or pressing backspace ← returns to the footnote marker.
Footnotes in action
This is a footnote marker.[1]
- ↑ This is a footnote that contains a citation or note.
Footnotes: the basics
To create the footnote marker, determine the point in the page content where the marker is desired and enter the markup with the citation or note inside the <ref>...</ref> tags. For example:
| Markup | Renders as |
|---|---|
This is page content.<ref>LibreOffice For Starters, First Edition, Flexible Minds, Manchester, 2002, p. 18</ref>
{{reflist}} |
|
- The {{reflist}} template will be explained in the next section.
The content inside the <ref>...</ref> will show in the reference list. The ref tags can be added anywhere a citation or note is needed. There must be content inside the tags, else an error will show.
The content of the ref tags can be formatted using most wikimarkup or HTML markup, although techniques such as the pipe trick and template substitution, will not work in footnotes. For example:
| Markup | Renders as |
|---|---|
This is page content.<ref>''LibreOffice For Starters'', First Edition, Flexible Minds, Manchester, 2002, p. 18</ref>
{{reflist}} |
|
The ref tag content may also contain an internal or external link:
| Markup | Renders as |
|---|---|
This is page content.<ref>''[http://www.example.or LibreOffice For Starters]'', First Edition, Flexible Minds, Manchester, 2002, p. 18</ref>
{{reflist}} |
This is page content.[1]
|
URLs must begin with a supported URI scheme. http:// and https:// will be supported by all browsers; however, ftp://, gopher://, irc://, ircs://, mailto: and news: may require a plug-in or an external application and should normally be avoided. IPv6 host-names are currently not supported.
If URLs in citation template parameters contain certain characters, then they will not display and link correctly. Those characters need to be percent-encoded. For example, a space must be replaced by %20. To encode the URL, replace the following characters with:
| space | " | ' | < | > | [ | ] | { | | | } |
|---|---|---|---|---|---|---|---|---|---|
| %20 | %22 | %27 | %3C | %3E | %5B | %5D | %7B | %7C | %7D |
Single apostrophes do not need to be encoded; however, unencoded multiples will be parsed as italic or bold markup. Single curly closing braces also do not need to be encoded; however, an unencoded pair will be parsed as the double closing braces for the template transclusion.
Reference lists: the basics
Once any number of footnotes have been inserted into the content, the reference list must be generated. For the basic reference list, add {{reflist}} wherever the list is desired. Once the page is saved and viewed, the footnotes will be automatically generated and numbered and the reference list will be generated. The main reference list is placed in a separate section, usually titled "References", "Notes" or the like.
| Markup | Renders as |
|---|---|
This is page content.<ref>''LibreOffice For Starters'', First Edition, Flexible Minds, Manchester, 2002, p. 18</ref>
==References==
{{reflist}} |
|
- When editing,
<references />may been seen instead of {{reflist}}. This is valid, but<references />does not offer the advanced features of {{reflist}}.
Footnotes: using a source more than once
You can cite the same source more than once on a page by using named footnotes. The syntax to define a named footnote is:
<ref name=name>content</ref>
To invoke the named footnote:
<ref name=name />
Names for footnotes and groups must follow these rules:
- Names are case-sensitive. Please do not use raNdOM capitalization.
- Names must not be purely numeric; the software will accept something like
":1"(which is punctuation plus a number), but it will ignore"1"(purely numeric). - Names should have semantic value, so that they can be more easily distinguished from each other by human editors who are looking at the wikitext. This means that ref names like
"Nguyen 2010"are preferred to names like":1". - Names must be unique. You may not use the same name to define different groups or footnotes.
- Please consider keeping reference names simple and restricted to the standard English alphabet and numerals. Failing that, if spaces are used, the following technical restrictions become relevant:
- Quotation marks are preferred but optional if the only characters used are letters
A–Z,a–z, digits0–9, and the symbols!$%&()*,-.:;<@[]^_`{|}~. That is, all printable ASCII characters except#"'/=>?\. - Inclusion of any other characters, including spaces, requires that the reference name be enclosed in quotes; for example,
name="John Smith". - The quote marks must be the standard, straight, double quotation marks (
"); curly or other quotes will be parsed as part of the reference name. - Quote-enclosed reference names may not include a less-than sign (
<) or a double straight quote symbol ("). These may be escaped with<and", respectively.
- Quotation marks are preferred but optional if the only characters used are letters
- You may optionally provide reference names even when the reference name is not required. This makes later re-use of the sourced reference easier.
| Markup | Renders as |
|---|---|
This is page content.<ref name=manchester2002>''LibreOffice for Starters'', First Edition, Flexible Minds, Manchester, 2002, p. 18</ref> This is more content.<ref name=manchester2002 />
{{reflist}} |
|
The actual name used can be most anything, but it is recommended that it have a connection to the citation or note. A major practice is to use the author-year or publisher-year for the reference name.
Note that the footnote labels are incremented in the order they are used, and that they use the same label when reused, thus the labels can seem out of order:
| Markup | Renders as |
|---|---|
This is page content.<ref name=manchester2002>''LibreOffice for Starters'', First Edition, Flexible Minds, Manchester, 2002, p. 18</ref> This is more content.<ref name=lexington2004>''OpenOffice for Experts'', Lexington, 2004, p. 18</ref> And even more content.<ref name=manchester2002 /> And again.<ref name=lexington2004 />
{{reflist}} |
|
Reference lists: columns
When using {{reflist}}, the list can be split into columns.
{{reflist|xxem}}where xx is the column width in em.
By setting the width in em, the number of columns will automatically be adjusted to the width of the display.
For example:
| Markup | Renders as |
|---|---|
Lorem ipsum.<ref>Source name.</ref>
Lorem ipsum dolor sit amet.<ref>Source name.</ref>
==References==
{{reflist|20em}} |
|
There is no hard rule on the column width to use, but some major practices include:
- 1 column (default): Where there are only a few footnotes; see Silver State Arena (23:05, 28 December 2012)
- 30em: Where there are a number of footnotes; see 1941 Texas hurricane (14:15, 8 February 2012)
- 20em: Where Shortened footnotes are used; see NBR 224 and 420 Classes (13:32, 1 August 2011).
Footnotes: list-defined references
Footnotes can also be defined within the reference list and invoked in the page content. This keeps all of the citations in one central location. The syntax is:
{{reflist|refs=
<ref name=name1>Content</ref>
<ref name=name2>Content</ref>
<ref name=name...n>Content</ref>
}}
The footnote markers are included as usual for a named footnote. For example:
| Markup | Renders as |
|---|---|
The quick brown fox jumps over the lazy dog.<ref name=LazyDog />
Amazingly few discotheques provide jukeboxes.<ref name=Jukeboxes />
How razorback-jumping frogs can level six piqued gymnasts.<ref name=JumpingFrogs />
==References==
{{Reflist|
refs=
<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>
}} |
|
The references will appear numbered in the order that they are referred to in the content, regardless of how they are ordered within the reference list. All references which are defined in the reference list must be uses, else an error message will be shown.
Previewing edits
When you edit a single section of a page, the footnotes list will not be visible when you preview your edits. Thus you ordinarily cannot see how your footnotes will later appear when you save your edits.
You can insert a {{Reflist}} into the edited section temporarily and remove it before saving; you will still not be able to see named references which were defined in other sections.
Tools that can be used are the User:Anomie/ajaxpreview.js script or the wikEd gadget.
Footnotes: groups
Sometimes it is useful to group the footnotes into separate lists, for example to separate explanatory notes from references, or to list references for tables, image captions, infoboxes and navboxes. The sequence of footnote labels is independent in each group. The syntax to define a footnote with a group is:
<ref group=groupname>Content</ref>
The syntax for the reference list with a group is:
{{reflist|group=groupname}}- The group name must not be enclosed in quotes.
Example:
| Markup | Renders as |
|---|---|
This part of the text requires clarification,<ref group=note>Listed separately from the citation</ref> whereas the entire text is cited.<ref>Citation.</ref> And this need even more clarification.<ref group=note>Another note</ref>
==Notes==
{{Reflist|group=note}}
==References==
{{Reflist}} |
|
- Note that the footnote labels in the reference list show only the numbers and not the group name.
Predefined groups
There are several predefined groups that can have a styled reference list such that the footnote labels match between the footnote marker and the footnote in the reference list. These predefined groups and reference lists have templates that make the markup simpler and also allow a standard reference to be inserted, so that an explanatory note can have a reference.
In these examples, the footnote labels match between the footnote marker and the reference list:
| Markup | Renders as |
|---|---|
Lorem ipsum dolor sit amet.{{efn|Footnote 1}} Cconsectetur adipisicing elit.{{efn|Footnote 2}} Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.{{efn|Footnote3}}
{{notelist}}
|
|
| Markup | Renders as |
|---|---|
Lorem ipsum dolor sit amet.{{efn-lr|Footnote 1}} Cconsectetur adipisicing elit.{{efn-lr|Footnote 2}} Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.{{efn-lr|Footnote3}}
{{notelist-lr}}
|
|
Issues
- Backlink labels are always styled as lower-alpha. This can be confusing when the {{efn}} is used.
- The entries in the reference list will show the default decimal styling if:
- The entries in the reference list will have no styling if:
- A reference is included in {{navbox}} or one of the variants and the style is set to
bodyclass=hlist; to resolve this, replace the style withlistclass=hlist.
- A reference is included in {{navbox}} or one of the variants and the style is set to
Reference lists: multiple use
Multiple reference lists may be included on a page. If each reference list uses a different group name, then there are no issues. If columns are set, then there are no issues. Multiple reference lists without group names or columns may be used, but they must be explicitly closed so that the references intended for one list do not appear in another list. To close a reference list, use:
{{reflist|close=1}}
For examples:
| Markup | Renders as |
|---|---|
This is a line of text.<ref>Reference 1</ref>
{{reflist|close=1}}
This is a 2nd line,<ref>Reference B</ref>
{{reflist|close=1}}
This is a third line.
<ref>Source C</ref>
{{reflist|close=1}} |
|
RefToolbar
You can use the citation toolbar to name references. When you first create a reference, you can enter a value in the "Ref name" box. When you want to reuse this reference, click the "Named references" button on the citation toolbar and choose which reference you would like to insert.
Footnotes: embedding references
Explanatory notes may need to be referenced. Due to limitations in the Cite software, reference tags cannot be nested—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. If the groupname is not specified, then the main and nested references will be rendered into the same reference list. Attempting to use #tag:ref more than once within list-defined references will result in a cite error.
Example:
| Markup | Renders as |
|---|---|
The quick brown fox jumps over the lazy dog.{{#tag:ref|A footnote.<ref>A reference for the footnote.</ref>|group="nb"}}
==Notes==
{{Reflist|group="nb"}}
==References==
{{Reflist}}
|
|
The syntax of #tag:ref is not obvious, as parameters must come after the content; {{refn}} may be used in place of the #tag:ref markup.
| Markup | Renders as |
|---|---|
The quick brown fox jumps over the lazy dog.{{refn|group="nb"|A footnote.<ref>A reference for the footnote.</ref>}}
==Notes==
{{Reflist|group="nb"}}
==References==
{{Reflist}}
|
|
Similarly, {{efn}} can simplify the usage of {{refn}}.
Footnotes: explanatory notes
Most footnotes are citations, which identify sources. Another kind of footnote is an explanatory footnote which is a comment that would be too detailed or too awkward to include in the body of the article. The Wikipedia Manual of style does not mandate a layout for explanatory footnotes at the bottom of the article, and in fact provides for several approaches that are acceptable. An important factor whether or not Shortened footnotes are used or not. Here are some common approaches to laying out the footnotes.
A
This example uses standard footnotes with all citations and explanatory notes in a single Notes sections:
| Markup | Renders as |
|---|---|
The Sun is pretty big.<ref>Miller, ''The Sun'', Oxford, 2005, p. 23. But Miller points out that the Sun is not as large as some other stars.</ref> But the Moon<ref>The Moon goes by other names, such as Selena - see, for example Brown, ''The Moon'', 2006, Penguin, p 623.</ref> is not so big.<ref>Brown, ''The Moon'', 2006, Penguin, p. 46. Historically the Moon was not always considered to be large. For a discussion, see Miller, ''The Sun'', Oxford, 2005, p 411.</ref> The Sun is also quite hot.<ref>Smith, ''The Universe'', Random House, 2005, p. 334.</ref>
==Notes==
{{Reflist}}
|
The Sun is pretty big.[1] But the Moon[2] is not so big.[3] The Sun is also quite hot.[4]
|
B
This example uses Shortened footnotes with a References section and combines explanatory notes and citations in a Notes section:
| Markup | Renders as |
|---|---|
The Sun is pretty big.<ref>Miller, p. 23. But Miller points out that the Sun is not as large as some other stars.</ref> But the Moon<ref>The Moon goes by other names, such as Selena - see, for example Brown, p 623.</ref> is not so big.<ref>Brown, p. 46. Historically the Moon was not always considered to be large. For a discussion, see Miller, p 411.</ref> The Sun is also quite hot.<ref>Smith, p. 334.</ref>
==Notes==
{{Reflist}}
==References==
* Brown, ''The Moon'', Penguin. 2001.
* Miller, ''The Sun'', Oxford, 2005.
* Smith, ''The Universe'', Random House, 2005.
|
|
C
This example uses list-defined references mixed with explanatory notes.
| Markup | Renders as |
|---|---|
The Sun is pretty big.<ref name=Foot01/> But the Moon<ref name=Foot02/> is not so big.<ref name=Foot03/> The Sun is also quite hot.<ref name=Foot04/>
==Notes==
{{reflist|refs=
<ref name=Foot01>Miller, ''The Sun'', Oxford, 2005, p. 23. But Miller points out that the Sun is not as large as some other stars.</ref>
<ref name=Foot02>The Moon goes by other names, such as Selena - see, for example Jones, ''The Solar System'', MacMillan, 2005, p 623.</ref>
<ref name=Foot03>Brown, ''The Moon'', 2006, Penguin, p. 46. Historically the Moon was not always considered to be large, see, for example Peterson, ''Astronomy'', MacMillan, 2005, p 623.</ref>
<ref name=Foot04>Smith, ''The Universe'', Random House, 2005, p. 334.</ref>
}} |
The Sun is pretty big.[1] But the Moon[2] is not so big.[3] The Sun is also quite hot.[4]
|
D
This example uses list-defined references and creates a separate notes section by using group names.
| Markup | Renders as |
|---|---|
The Sun is pretty big.<ref name=Foot01/><ref group=Note name=Note01/> But the Moon<ref group=Note name=Note02/> is not so big.<ref name=Foot02/><ref group=Note name=Note03/> The Sun is also quite hot.<ref name=Foot03/>
==Notes==
{{reflist|group=Note|refs=
<ref name=Note01>But Miller points out that the Sun is not as large as some other stars.</ref>
<ref name=Note02>The Moon goes by other names, such as Selena.</ref>
<ref name=Note03>Historically the Moon was not always considered to be large.</ref>
}}
==References==
{{reflist|refs=
<ref name=Foot01>Miller, ''The Sun'', Oxford, 2005, p. 23.</ref>
<ref name=Foot02>Brown, ''The Moon'', 2006, Penguin, p. 46.</ref>
<ref name=Foot03>Smith, ''The Universe'', Random House, 2005, p. 334.</ref>
}} |
|
E
This example is similar as the previous one above, except that it allows references embedded within footnotes.
| Markup | Renders as |
|---|---|
The Sun is pretty big.<ref name=Miller2005/>{{efn|But the Sun is not as large as some other stars.<ref name=Miller2005/>}} But the Moon{{efn|The Moon goes by other names, such as Selena.<ref name=Jones2005/>}} is not so big.<ref name=Brown2006/>{{efn|Historically the Moon was not always considered to be large.<ref name=Peterson2005/>}} The Sun is also quite hot.<ref name=Smith2005/>
==Notes==
{{notelist}}
==References==
{{reflist|refs=
<ref name=Miller2005>Miller, ''The Sun'', Oxford, 2005, p. 23.</ref>
<ref name=Jones2005>Jones, ''The Solar System'', MacMillan, 2005, p 623.</ref>
<ref name=Peterson2005>Peterson, ''Astronomy'', MacMillan, 2005, p 623.</ref>
<ref name=Brown2006>Brown, ''The Moon'', 2006, Penguin, p. 46.</ref>
<ref name=Smith2005>Smith, ''The Universe'', Random House, 2005, p. 334.</ref>
}} |
|
Footnotes: page numbers
Suppose you would like to cite one book, but different facts appear on different pages. You would like to cite the book again and again, but point each fact to the proper page. Suppose one fact is on page 8, a different fact on page 12, a third fact on page 18, a fourth fact on page 241. You could put a line in the "pages" parameter saying "see pages 8, 12, 18, 241" but a fact-checker might have to check all of them before figuring out the right one. Or, you could duplicate the entire citation for the book in each instance, but that would be redundant. One common approach is to use shortened citations, which requires the use of a References section following the footnotes section. Another approach is to attach a {{rp|8}} right after the reference pointer.Template:Listref and replace the "8" with the appropriate page number.
For example:
| Markup | Renders as |
|---|---|
Schudson said the Constitution shaped citizenship in fundamental ways.<ref name="Schudson">{{Cite book
| last = Schudson
| first = Michael
| title = The Good Citizen: A Brief History of American Civic Life
| publisher = Simon & Schuster
| date = 1998
| url = http://books.google.com/books?id=aawMAQAAMAAJ
| isbn =0-684-82729-8 }}</ref>{{rp|8}} But elections in early American politics did not generate much interest<ref name="Schudson"/>{{rp|12}} while "open discussion of differences" was generally avoided.<ref name="Schudson"/>{{rp|18}} Citizenship later shifted to a polity of essentially "self-absorbed citizens", according to his analysis.<ref name="Schudson"/>{{rp|241}} |
Schudson said the Constitution shaped citizenship in fundamental ways.[1]:8 But elections in early American politics did not generate much interest[1]:12 while "open discussion of differences" was generally avoided.[1]:18 Citizenship later shifted to a polity of essentially "self-absorbed citizens", according to his analysis.[1]:241
|
When using list-defined references, {{r}} can be used for the same style of in-text page references.
Limitations
- Templates can not be substituted within
<ref>...</ref>tags.{{subst:foo}}will remain as-is. <ref>tags can not be nested. See #Embedding references within footnotes above for solution.
See also
- Template:Harvard citation#Using CITEREF directly and {{sfnref}}
- Wikipedia:Citing sources/Further considerations—a how-to article with some additional considerations for citing sources
- Wikipedia:Help desk—to ask questions about using footnotes in articles if you were not able to find the information you need on this help page.
Notes
cs:Wikipedie:Reference es:Wikipedia:Referencias#Notas al pie