Because art historians frequently emerged from classical studies, these two sources may scare up articles or book citations. Consider these standard sources within classical studies for art as well.
New Pauly Online - The classical scholarly world's encyclopedia. Signed articles (ie, you can quote them in your papers), reliable data, core bibliography.
don't forget THE SECRET WEAPON PQDT (Dissertations full-text) - 90% full text, super scholarly, keyword searchable, unique primary sources often in the back as appendices (more here)
L'Annee Philologique - the standard index for the ancient world. All civilizations and topics.
- TIPS: Advanced Search -► under THEMATIC SEARCH ► click "More Search Possibilities" ► next to "All Index Fields" type in Greek (or whatever area).