Even if your professor doesn't tell you to cite your sources, you still have too. Chances are, if they didn't tell you, they just assumed you know it's required. Any source you get information from whether it is an interview with a person, a pamphlet from a government office, a web page, a journal article, a book, etc. requires a citation. When you use that sources' information, you must give them credit; if you don't you, you are plagiarizing.
There are numerous citation styles. Which one you use often depends on the discipline.
Below are guides for these three most commonly used citation styles:
Citing your sources is one of the most important steps in doing research. RefWorks will allow you to store and organize your citations as well as easily create your bibliography/references (whether annotated or not) and final paper in the correct style.
You can use RefWorks to: