Template:Citation

The Citation template generates a citation for a book, periodical, contribution in a collective work, patent, or a web page. It determines the citation type by examining which parameters are used.

If invoked with the right parameters, this template produces output identical to that of the Cite templates, such as cite book and cite web. The default behavior sometimes differs from that of the Cite templates; for example, this template by default generates anchors for Harvard references whereas the Cite templates do not, and this template by default uses commas to separate some fields that the Cite templates separate with periods.

All parameter names are lowercase.

Anchored citations
This template can generate a citation that can be combined with shortened footnotes or parenthetical referencing. It does this by creating an HTML anchor containing an ID. The special parameter harv generates an ID suitable for Harvard referencing templates such as harv as specified in the next section; this is the default for the citation template. If an empty ref is given, no anchor is generated; this is the default for the Cite templates such as cite book and cite news. You can also specify the ID directly, using the ID parameter. For example, suppose an article's References section contains the markup: which generates the citation: Then, the markup " " generates a parenthetical reference "(Freud 1930)" containing a wikilink to the citation (try clicking on the wikilink).

Anchors for Harvard referencing templates
IDs compatible with Harvard referencing templates such as harv are computed from the last names of the authors and the year of the cited source. For example, the markup " " generates the Harvard reference "", which wikilinks to the citation whose markup and appearance are shown below: In this example the citation template defines, and the harv template uses, the HTML ID " ", composed by concatenating the string " " with the last names of the authors and the year. The harvid template can be used to generate such IDs, for example,  generates " ".

The names of only the first four authors are used; other author names are not concatenated to the ID. If no author names are given, editor names are used instead. For patents, inventor names are used instead of authors or editors. If these names are not given, this template does not generate an anchor.

Last names are used, as specified by the parameters last1 (or last), last2, last3, and last4, and similarly for editor1-last etc. and for inventor1-last etc. If a full name is given but no last name is specified, this template falls back on the full name, but this usage is not recommended. For example, in " " no last name is given, so this citation cannot be combined with the Harvard reference " ". To make these citation and harv invocations compatible, either replace "Sigmund Freud" with "Sigmund Freud", or add "ref" to the citation invocation, or add the same ref parameter (say, "EgoId") to both the citation and the harv invocations.

Similarly, the year is used, as specified by year. If no year is given, this template attempts to derive the year from date (or, if no date is given, from publication-date) by applying the MediaWiki #time function. This heuristic works with many common date formats but has known problems, so when in doubt it is safer to use year.

IDs must be unique
Names, years, and hand-specified IDs must be chosen so that the IDs are unique within a page; otherwise the HTML will not conform to the W3C standards, and any references to the citations will not work reliably. For example, suppose a page contains the following two citations with harv-compatible IDs:



If these citations were altered to say "2008" rather than "2008a" and "2008b", the resulting page would not work, because the two different citations would both attempt to use the ID " ". To avoid this problem, distinguish the citations by appending suffixes to the years, e.g., "2008a" and "2008b", as was done above. Any Harvard references to these citations should use years with the same suffixes.

It is good practice to verify that a page does not contain duplicate IDs by using the W3C Markup Validation Service; see External links.

Tools
See Citing sources for a list of tools which can help create a reference in the 'citation' format.