It is crucial that you cite your sources to give credit to the author you are referring to. Failing to do so will result in Plagiarism.
Styles commonly used at AUB are MLA, APA and Turabian.
If you are not sure which citation style you should use, ask your instructor.
For sample styles, check the manuals at the Reference Desks or look at some samples from other universities.
For more, check this guide: How to Cite your Sources