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Citation Styles & Tools

A brief explanation of citation fundamentals and a guide to useful resources.

Which Citation Style Should I Use?

This guide provides an overview of the resources available for the three most common citation styles, APA, MLA, and Chicago/Turabian. Broadly speaking, they are used by discipline as follows:

Citation Styles by Discipline
APA Social sciences, education, business
MLA Art, literature, philosophy
Chicago/Turabian History

Some disciplines, such as law and medicine, use more specialized styles. If you're not sure which style you should be using, ask your instructor.

Please use the navigation column on the left to find the resources you need.

Why Do We Cite?

Why we cite our sources:

  • To give credit where it's due. We all owe a debt to the scholars and researchers who came before us, and this is how we acknowledge it in the Western academic tradition. By citing them, we enhance the profile of their work.

  • To support the integrity and reliability of our own scholarship.

  • To provide future scholars and researchers with a means of tracing the evolution of ideas and information in a particular field or topic.

What Should I Cite?

Common Knowledge

Some information does not need to be cited. "Common knowledge" is basic, unremarkable information that most people in a given cultural context would know without needing to look it up. For example, most people living in the United States know that George Washington was the first American president, and therefore you could include this information without a citation. However, if you expanded on this in the same sentence by writing "George Washington, the first president, was descended from British royalty," you would need to cite a reliable source, since Washington's ancestry is not common knowledge.

Here's another example:

"McDonald's is a chain of fast food restaurants."

Pretty obvious, right? However, if you wrote the following, you would need a citation:

"McDonald's signature burger, the Big Mac, contains 563 calories."

You would probably be safe if you just wrote that the Big Mac is the chain's signature burger, but caloric information is something that needs to be supported, such as by an online menu. This is true of most statements that include numerical facts or figures, excluding, once again, basic facts that mostly everyone in the United States (and many people outside of it) would know, such as the fact that there are 50 states.

What Needs to be Cited?

  • Facts and figures that do not qualify as common knowledge. An exception would be information you know from personal observation or experience. For example, if you write that there are five houses on the street where you grew up, that statement does not require a citation.
  • Opinions expressed by groups or individuals. Without citations, these are nothing but "he said, she said."
  • Direct quotes, regardless of the source. This applies to any time you use more than a few words in sequence, unaltered, that were spoken or written by someone else.
  • Paraphrased information or passages. Paraphrasing describes a situation in which you take information from a source but render it in your own words.
  • Data from charts, graphs, timetables, etc.
  • Music or imagery, even if it came from a free Web source and is not subject to copyright restrictions.