Choose the appropriate citation style from this page. And remember to look at the notes at the bottom of each page for the explanations behind the examples. Keep in mind these apply to formatting a bibliography only.
For additonal information on in-text citing, scroll down on this page and choose either Research and Documentation Online or OWL-Purdue's Online Writing Lab.
If what you need is not on these pages, go to the Reference Desk and ask for the MLA Handbook or the APA Publication Manual or other style manuals that might be preferred by your professor.