Zotero is a free, open source utility that works in your browser to help collect, manage and cite sources. It was developed at George Mason University. Highly recommended.
Manage your sources from start to finish with an integrated reference manager. Both of these reference managers are free, and both support APA style.
A free reference manager and academic social network. Users can automatically generate bliographies, collaborate with other researchers online, import papers from other research software, find relevant papers, access papers from anywhere online, and read papers on the go with iPhone app.
The official site for the Chicago Manual of Style, includes common examples of materials cited in the style - both author-date and notes & bibliography.
This website suggests information sources for different disciplines, explains how to cite them in APA, Chicago, MLA and CSE, and provides example papers
