BibMe

From Them:

BibMe is your one-stop source for all your bibliography needs!  Don't remember all the information for the source you cited? No problem! BibMe allows you to search from a database of millions of entries to find your source and AutoFill in the information. Or, if you have the source in front of you, you can enter your entries in manually. BibMe also offers resources to help you cite your work properly in the 'Citation Guide' section.