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Citing Sources: Understanding Citations

This guide indicates the appropriate form for layout, in-text citations, and bibliography for MLA, APA, and Chicago formatted papers.


Why is citing necessary?

A citation is used to refer to a particular source of information such as a book, article, website, video, or interview.

Citations include the information for the reader to find the original source of information. This is an important step in establishing credibility in your writing. Properly citing sources is an important part of academic honesty and avoiding plagiarism. Remember, you must cite any time you use information from a source which includes directly quoting the source, paraphrasing, or borrowing an idea.

Cite your sources because...

  • Citing strengthens your writing.
  • Citing reveals that you have researched your idea and synthesized all the information into your own body of work.
  • Citing shows that you have reached beyond your own world and listened to the ideas of others.
  • Citing someone else shows that other important people support your own thoughts. 
  • By quoting oppositional thoughts, you demonstrate that you have thought about both sides of an issue.
  • Citing makes you sound intelligent and will probably improve your grade.
  • It is the RIGHT thing to do!

Source: "Tools for Students." WSWHE BOCES. Web. 16 Feb. 2015. <>.


At St. Paul's, three different citation styles are used: MLA, APA, and Chicago. Each has its own set of rules about how the information is presented. Which style is used is usually determined by your subject area. Make sure you check with your teacher to ensure you are using the appropriate style.

Citations are included in two sections of your paper. The full citation is included in the bibliography (also known as the Reference page or Works Cited page). A shortened version, known as an in-text citation, is included in the text of your paper.

The following video explains in-text citations using MLA formatting. Please note, a bibliography in MLA is called a Works Cited page. Please review the rules of MLA for more information on this formatting style.

When to Use an In-text Citation

Created by Cardiff University Informmation Services. Used under a Creative Commons Attribution-NonCommercial 3.0 Unported License

To summarize:

  • If you had to go to a source to find the information, cite it.
  • If all the information in a paragraph comes from the same source, you may cite at the end of the paragraph. If, however, you have used more than one source in the paragraph, provide the citation after the material borrowed.