Turabian & Chicago Styles - From the work of Kate Turabian at the University of Chicago and the University of Chicago Press. Often preferred in history.
Chicago Format:
Author's Last Name, First Name Middle Initial. Title of Book: Subtitle of Book. edition. Place of Publication: Publisher, Year. Name of Database. Place of access. Web. Date of access.
E-book Example:
Baracchi, Claudia. Of Myth, Life, And War In Plato's Republic. (Indiana University Press, 2002), accessed February 15, 2013, eBook Collection (ENGCOhost).