As explained in the term paper guidelines, you are free to use any of the following five citation styles: MLA, APA, Harvard, Chicago, or Turabian, with the caveat that you must follow the style guidelines for whichever style you choose to the letter.
Here is a link to a University of Pittsburgh page that gives some help with the MLA, APA and Chicago/Turabian styles: Pitt Citation Help. (Links to an external site.)
Here is a link to a page that provides guidelines for using the Harvard citation style: Harvard Style. (Links to an external site.)