EndNote is a program that provides a storage space for citations (references to works you use in your writing) and formats them in any of thousands of citation formats as you write your paper, annotated bibliography, dissertation, or publication. Go here for more information.
Zotero is a Firefox Add-On that provides a storage space for citations (references to works you use in your writing) and formats them in any of hundreds of citation formats as you write your paper, article, annotated bibliography, dissertation or book. Go here for more information.
To use Zotero you must have the Firefox browser. If you don't have it, you can download Firefox at http://firefox.com.
In Firefox, go to http://zotero.org to download the latest version of Zotero.
Ask your professor which citation format you should use, MLA, APA, Chicago, or Turabian. The MU Libraries have style manuals on reference and also links to websites outlining basic citation styles.
When you're doing research, for every source you consult you want to record the:
Source (name of publication)
Publisher (for books)
City of publication (for books)
Web site address
Date accessed (for web sites)
My favorite sites for citation help are at Duke University:
You can find other assistance online via the MU Libraries' homepage. Go to http://library.missouri.edu/guides/WritingCiting.htm.