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Research Guides

What is a Citation?

A citation is the information needed to identify a resource: a book, article, Web site, etc. Citations are included in bibliographies or works cited statements at the end of books, book chapters, articles and research papers. It is important to acknowledge your sources as accurately as possible so that readers can consult the articles and books that you used in your research.

--The University of Arizona Library

Perhaps even more important though, citing a source is a way of participating in an “intellectual conversation” and is a way for “you to demonstrate your link to the community in which you work.”

--Yale College Writing Center

Citation Format

Different subject disciplines call for citation information to be written in very specific order, capitalization, and punctuation. There are therefore many different style formats. Three popular citation formats are MLA Style (for humanities articles) and APA or Chicago (for social sciences articles).

Chicago sample for print journal article:
Whisenant, Warren A. "How Women Have Fared as Interscholastic Athletic Administrators Since the Passage of Title IX." Sex Roles 49, no. 3 (2003): 179-182.

Citing Images

Images must be cited like all other resources. If you use an image you did not create, you must provide a citation. Images should be cited in all cases, even if the image is very small, or in the public domain. The citation should be accessible in the context of the image's use (within a Powerpoint presentation, on a web page, in a paper, etc.).


Image citations should include the following information at a minimum:


  • Title
  • Creator name
  • Repository information (museum, library, or other owning institution)
  • Image source (database, website, book, postcard, vendor, etc.)
  • Date accessed


It is also useful to include date, culture, and rights information, if known.


Image citations can be formatted according to the citation style you are using.


MLA 2009 Style (examples from the Owl at Purdue)


Goya, Francisco. The Family of Charles IV. 1800. Museo Nacional del Prado, Madrid. Museo National del Prado. Web. 22 May 2006.


Klee, Paul. Twittering Machine. 1922. Museum of Modern Art, New York. The Artchive. Web. 22 May 2006.


Digital images are an electronic resource that need to be used responsibly. Most databases and web sites provide information about how their images can be used. It is important to read this information carefully, and comply with all usage guidelines. Usage guidelines can vary considerably, so be alert to differences and details.

Online Resources for Citation Styles

Get Organized! Citation Management Tools

These are web-based personal citation databases and bibliography creators that allow you to import, store, and share your research citations and automatically format your bibliographies into whatever style you need (MLA, APA, Chicago, and more).