Check with instructor on the preferred style he or she wishes you to use and be sure to conslult the most up-to-date edition of that style manual.
Simple free online source. Also good if you can't access UST subscription to RefWorks.
Free sophisticaled, open source online citation tool, easier to use than RefWorks. Zotero works with Firefox for Windows, Mac and Linux but not Internet Explorer (IE) or Google Chrome. Also good if you can't access UST subscription to RefWorks.