Citations let your professor, or anyone else who reads your work, find the items you used in your research. The key to a successful citation is providing all the information needed for your reader to find the book, article, or other item you are citing.
Citing builds your credibility and shows that your ideas are shared by other experts in the field. Citing scholarly, peer-reviewed sources lends extra credibility to your work.
Citation avoids plagiarism! Citing your sources properly gives credit to the original author.
Information originally found at the library for american.edu