Duke's Rare Book, Manuscript and Special Collections Library has untold unique resources. Because of the nature of its collections, its riches are not as discernable through the Duke catalog. In addition to doing a search limited to Rubenstein Library, email or query a special collections librarian for a consult on what may be of interest. RUBENSTEIN SEARCH
Reference Sources - scope out an area, provide brief, better bibliography and key words (author's names, nomenclature) for more extensive searching.
Groveart (Oxford Online) - Scholarly art encyclopedia. Entires on classical, also use for terms and other art topics related (Asia Minor, etc.)
Brill's New Pauly - combined classical-subject reference works, the most important of which is the Pauly (English).
Oxford Reference Online: Classics - Oxford University Press online titles on classical studies
Lexis - full-text newspaper index going back +10 years. Great for seeing classical context in modern times
Dukecatalog example, for sculpture in the classical world, use the subject heading, Sculpture--Greece
Perseus Project - Classical studies website maintained by Tufts University. Compendium of texts and images.
Claros - The World of Art on the Semantic Web - Oxford University's classical art website (images)
AWOL - Ancient World On Line - serious blog for the study of the Ancient world.