Billed as your personal research assistant, Zotero is a free online tool that helps you collect, organize, cite, and share research.
Please see the University of California-Berkeley's exhaustive library guide to using Zotero here.
Register for a free Zotero account here.
Consult the UC Berkeley library guide about how to use Zotero.
ZoteroBib helps you build a bibliography from any computer or device without creating an account or installing software.