Reference sources are encyclopedias, dictionaries, and other materials used for quick facts and background information.
For information on the Middle Passage, search
Gale Virtual Reference Library
Credo Reference - Middle Passage
Falola, Toyin, and Amanda Warnock. Encyclopedia of the Middle Passage. Westport, Conn: Greenwood Press, 2007.
(Click the link to find the book in the library catalog.)