Citing Your Sources: Citing Basics

The Williams Honor System requires you to properly acknowledge sources you have used in course assignments. This guide provides basic information on how to cite sources and examples for formatting citations in common citation styles.

Why is Citing Sources Important?

  • To give credit to ideas that are not your own
  • To provide support for your argument
  • To enable your reader to find and read the sources you used
  • To avoid Honor Code infractions

What Needs to be Cited?

  • Exact wording taken from any source, including freely available websites
  • Paraphrases of passages
  • Summaries of another person's work
  • Indebtedness to another person for an idea
  • Use of another student's work
  • Use of your own previous work

You do not need to cite common knowledge.

What's Involved in Citing Correctly?

In most citation styles, two parts are needed:

  1. An in-text citation
    Whenever you refer to the work of another person, you must indicate within the text where you got the information. The in-text citation provides a brief reference and points your reader to the complete citation.
  2. A list of works used
    The final page of your paper is usually a list of resources you cited or consulted.

Use the tabs above to learn about these two parts in your chosen citation style.

What Citation Style Should I Use?

Use the style recommended by your professor or choose one of the major styles below based on the discipline for your paper:

  • ACS (American Chemical Society) for chemistry
  • APA (American Psychological Association) for psychology and other social sciences
  • CSE (Council of Science Editors) for biology
  • Chicago (University of Chicago Press)
  • MLA (Modern Language Association) for literature, arts, and humanities

What is Common Knowledge?

Widely-known, generally-accepted information that is not attributable to one source.


  • Columbus Day is a national holiday that celebrates the arrival of explorer Christopher Columbus to America in 1492. (common knowledge, no citation needed)
  • Many institutions, including Williams College, now recognize the holiday as Indigenous Peoples Day. (common knowledge, no citation needed)
  • South Dakota was likely the first state to officially recognize Indigenous Peoples Day as a state holiday.1 (not common knowledge, citation needed)

What is considered common knowledge can be tricky. When in doubt, ask your professor!

1. Delkic, Melina. "Indigenous Peoples Day, Explained." New York Times, October 9, 2022,