Cite Right by Good eBook for citation assistance - but not the most up to date for MLA and other styles!
MLA Handbook by The Modern Language Association, the authority on research and writing, takes a fresh look at documenting sources in the eighth edition of the MLA Handbook, the official guide to MLA format.
Publication Manual of the American Psychological Association by The seventh edition has been thoroughly revised and updated to reflect best practices in scholarly writing and publishing.
Publication Manual of the American Psychological Association by 
A Manual for Writers of Research Papers, Theses, and Dissertations by Turabian is a simpler version of Chicago style meant for students who are writing materials that will not be published. The Turabian guide is shorter and includes information on formatting rules, the basics of researching and writing academic papers, and citation style.650 E Parkway S, Memphis, TN 38117 · (901) 321-3432