Simple free online source.
Which should you use?
Ask each of your professors which style they want you to use. If they have no preference you can follow and of these style, although most of our Seminary students are asked to use either the MLA or Turabian Style Manuals.
Print versions of these style manuals contain examples of citing more sources than these web pages do, as well as other things you may need to know, such as margins, font size, etc.