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About Citation Styles

There are thousands of citation styles in use. Your lecturer, course director or supervisor may tell you to use a particular one, or allow you to choose one on your own.

Guides for each style will tell you how to format the references:

  • Details on which order to present the bibliographic information.
  • Grammar instructions such as how to use punctuation and capitalisation - what is emboldened, underlined, italicised… where the full stops and commas go…
  • Different rules will apply to different formats of sources (journal articles, book with one author, books with several authors, edited books, chapters in edited books, webpages, reports, films, etc. etc…)

Many different styles are in use in Trinity College Dublin - for definitive answers you should use the full style manual for each system.

About Numbered Styles

Numbered styles list references in the order they are mentioned, using a digit in the text to refer to the fuller citation at the end.

If a reference is mentioned again later, it reuses the same number.

The most common numbered style is Vancouver - while this style has its own particular rules, numbered styles in general are often referred to as Vancouver styles.

About Inline Styles

Inline citations use a brief summary of the reference in the text (such as listing the author and date, or the author and title, or author and page) with the full reference stated at the end of the chapter or work.

This final list is called a reference list or bibliography.

Generally the full list of references will be in alphabetical order by the first author’s surname.

Inline styles are sometimes called the “Harvard” style as they were first used at Harvard in the 1880s. They are also called “Parenthetical” styles as they enclose the partial information in brackets.

Two of the most popular Harvard-type styles are the APA 7th Edition, and the MLA 7th Edition. The Library has books on these (and other) styles available to guide students on how to reference correctly.

About Footnote Styles

Like numbered styles, footnote styles give the reference an ascending number in the text and the full references are listed in that order at the bottom of the page in a footnote. A full list at the end of the work or chapter may also be required - although unlike with numbered styles, this may be in alphabetical order by surname, rather than in order of mention.

The Chicago style is the most well-known footnote style. In Chicago and other footnote styles there are rules that apply if you use a work again in another footnote. Up until the Chicago 16th Edition, If you mention the citation again as the next footnote, then the term “ibid” (“in the same place”) is used instead of the reference. If it is used again after referring to a different citation, then a short form of the reference is used in the footnotes - the manual for the style will tell you what this should look like. However, this was changed in the Chicago 17th Edition, with the short form now favoured over ibid even if mentioned immediately afterwards.

Subject Librarian

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Greg Sheaf
2nd Floor, Ussher Library
(01) 8962928
Subjects: Chemistry, Physics