The workhorse of the inline style is the <ref> tag. Notes and citations are placed in between a pair of <ref> tags in the text itself, where you want the footnote to appear. For example,

According to scientists, the Sun is pretty big<ref> Miller, E: "The Sun", page
23. Academic Press, 2005</ref>, however the moon is not so big.<ref>Smith, R:
"Size of the Moon", ''Scientific American'', 46(78):46</ref>.

This example cites two sources: a work by E. Miller published by Academic Press and a work by R. Smith published in Scientific American. The references will only display in the text as a numbered link to a footnote, which appears directly where you have placed the first <ref> tag. These numbers automatically update whenever a new footnote is added.

For a reader to actually see the references cited, you must add a second piece—the <references/> tag, which is inserted at the bottom of the article in a section called References or Notes. The text of all footnotes will appear wherever you place this tag (though placing <references/> before <ref> doesn't work). For instance, for the previous example, you would create a section that looks like this:

==Notes==
<references/>

Don't add anything to the <references/> tag; the linked references from the text will automatically display here:

==Notes==
# ^ Miller, E: "The Sun", page 23. Academic Press, 2005
# ^ Smith, R: "Size of the Moon", ''Scientific American'', 46(78):46

Each footnote starts with a caret (^), which is automatically linked back to the text where the reference was placed. To edit the reference, you change it directly in the article text rather than in the References section.

Though you don't need to add anything to the <references/> tag, you can list other, non-footnoted references in this section as well. Creating two sections, one called Notes (for footnotes) and one called References (for all other references) is better, however. This form also enables you to use short references in the footnotes (such as "Smith, p. 47"), as long as you spell out the full reference in the References section.

You can use the same footnote (that is, the same citation), and hence the same footnote number, more than once. To do this, insert the name variable in the <ref> tag, like this:

According to scientists, the Sun is pretty big<ref name="sun"> Miller, E: "The
Sun", page 23. Academic Press, 2005</ref>, however the moon is not so big.<ref
name="moon">Smith, R: "Size of the Moon", ''Scientific American'', 46(78):46</ref>.

To refer to each of these citations at a later point, you only need to refer to the abbreviated form of the reference with ref name:

The sun is also very hot <ref name="sun"/>. The moon, however, is cold <ref
name="moon"/>.

Be sure to add that last ending slash, or all the text after the reference won't display when you save the page!

These two references then use the same footnote numbers as the first reference using that name. In the footnotes section, links to each instance of the reference will appear next to the footnote that is used multiple times, labeled alphabetically: a, b, c, and so on.

Using ref name is the best way to cite a source multiple times within the text. The old academic convention of ibid. (short for ibidem, meaning this is the same book as mentioned in the previous note, but on a different page) is not robust enough. Someone could later add a footnote between your successive notes, and the second note wouldn't make sense. The inline system works because if text is edited or moved, the numbers follow automatically. Unfortunately, one limitation of the current footnoting system is that if you want to change any part of the cited reference (such as to cite a different page number) ref name doesn't work; you have to type out the entire reference again. If this becomes time consuming in a long article, consider using the short reference style in a Notes section with the full references in a separate References section.

Many templates have been developed for formatting citations. You can use templates to ensure that cited references for different types of sources (such as newspapers, books, etc.) are clearly displayed in a standardized way. You can also use citation templates both for formatting citations in footnotes or citations listed separately in a References section.

In a citation template, the editor fills in the template parameters with the source information (such as the author, title of the work, and so on) and the template automatically arranges the citation appropriately, according to the type of source. For instance, here is the wikitext of the citation for an online newspaper story using the {{news}} template:

{{cite news |last=Plunkett |first=John |url=http://media.guardian.co.uk/site/
story/0,14173,1601858,00.html |title=Sorrell accuses Murdoch of panic buying
|publisher=The Guardian |date=2005-10-27 |accessdate=2005-10-27}}

When you save the page, the reader sees the following citation:

Plunkett, John. "Sorrell accuses Murdoch of panic buying", The Guardian,
October 27, 2005. Retrieved on October 27, 2005.

with the title of the article linked to the given URL. Templates do the work of making sure citations are correctly formatted. They also help ensure that references include all the necessary information—not just a URL for a website but also a date—so articles can be accessed from an archive if the URL no longer works.

Some templates have been created for specific sources that are commonly cited. In this case, the main source information is already encoded in the template, so the editor only has to add variable information such as author name or article title. The full source citation will appear when the page is saved. For instance, the template {{Fishbase_species}} is for adding a link to FishBase, a scholarly online database of information about fish. In the [[Guppy]] article, the following citation appears:

{{FishBase_species|genus=Poecilia|species=reticulata|year=2004|month=April}}

The editor only fills in the genus and species information and the date that the site was accessed. The saved page renders this as the following citation:

"Poecilia reticulata". FishBase. Ed. Ranier Froese and Daniel Pauly. April 2004
version. N.p.: FishBase, 2004.

The title of the database, the editors, and the formatting of the citation are all encoded in the template. This is clearly useful if you're citing the same source multiple times. A list of specific source templates can be found at [[Category:Specific source templates]].

One problem with templates is that they are inflexible; for instance, if you want to wikilink the author name in the news example given, you'll have trouble because the author first and last names are in different fields. There are two solutions for this particular problem: Either don't use the template and write the citation out by hand, or add an extra field that has been developed just for this called authorlink, which can be filled out like |authorlink=[[John Plunket]] (for joint authors, you can use authorlink1= and authorlink2=).

As you can see, templates can get complicated. They can also make the wiki markup denser and harder to read, especially if they are used for in-text citations, and they may not add that much to the presentation of references. Templates are certainly optional. They can also be added gradually: Existing references can be converted to templates over time. More information about citation templates can be found at [[Wikipedia:Citation_templates]].