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Citing Sources & Plagiarism: How Citations Work

Citations and Scholarly Communication


There are several specific styles of citations, but all have the same idea: When you borrow another person's ideas or information, you explicitly say in your paper what is borrowed and where you found that information. (See examples in the box below.)

Use "quotation marks" and cite your source when you use another writer's exact words.


You also need to cite when you use someone else's ideas. You are still borrowing ideas from another author- even if you change some of the words, also called "paraphrasing." If you fail to cite paraphrased writing, you will be guilty of plagiarism.


A bibliography or Works Cited listing is a complete list of sources --- books, articles, web pages, email, interviews, videos, lectures, etc. --- that you used in preparing you paper. It appears at the end of your writing. Different style formats have different names for the bibliography. A list of sources in MLA style is called Works Cited. The list of sources in APA style is called References. 

Remember, by citing your sources, you will protect yourself from charges of plagiarism.


Common knowledge requires no citation:

Clouds are composed of water or ice particles

Quotations require a citation:

"Evidence is accumulating that human activities are influencing clouds in ways that can in turn influence the environment" (Ghan 171).

Works Cited (listed on a separate page)

Ghan, Stephen. "Clouds." Encyclopedia of Climate and Weather, edited by Stephen H. Schneider. Oxford Press, 1996. 

Paraphrasing requires documentation:

There's growing evidence that the activities of humans have an effect on clouds and thus the environment (Ghan).

Works Cited (listed on a separate page)

Ghan, Stephen. "Clouds." Encyclopedia of Climate and Weather, edited by Stephen H. Schneider. Oxford Press, 1996.

Do I Have to Cite Everything?

Common Knowledge:

One of the hardest parts of documentation is deciding how far to go in citing sources. If you mention that Los Angeles suffered an earthquake in January 1994, do you have to show where that information came from? No. Even if you didn't really know that for sure on your own. This is considered "common knowledge."

This can get tricky. When in doubt it is probably a good idea to include the documentation. Ask a librarian or your instructor for advice on specific situations.

Quotes vs. Paraphrases

What is the difference between a quotation and a paraphrase?

A quote takes the exact words from a source and copies them into your paper. You use quotation marks and cite the source the words came from.

A paraphrase uses the ideas from a source but you rewrite it in your own words. You do not use quotation marks, but you still have to cite the source you used. Paraphrases are usually a shorter summary of the ideas. Paraphrases can be mixed in with your own ideas as long as it's clear which is which.

If you want more information on this tricky topic, take a look at these:

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