A citation identifies information you have used in writing your paper. You can cite books, articles, videos, speeches and more. A listing of citations can be called a "bibliography" or "works cited" or simply, "references."
You must cite your sources whenever you use someone else's words, images, or ideas to give that person credit for his/her intellectual property. Citing sources is also necessary so the reader can find the information you used in your research. Citing sources will help you avoid plagiarism.
Plagiarism occurs when you use someone else's intellectual property without properly crediting them, and it is a serious offense. Always cite your sources whether you quote or paraphrase.
To avoid plagiarism, you must give credit whenever you use:
To learn more about plagiarism and how to avoid it, check out Highline Library's Plagiarism Tutorial or this tutorial on What Every Student Needs to Know about Plagiarism.
To see the differences between citation styles, see this chart from the OWL at Purdue has a chart.