Zotero: The Tri-College Libraries recommend Zotero, a free online app that can format your bibliography, keep your citations organized, and even save your articles in the cloud so you can access them later from the library, home, or a cafe.
EndNote Web: The Tri-Colleges provide free access to EndNote Web.
Any librarian will be happy to give your a tour or a few pointers of the software.
See the Chicago Manual style guide for more information (this is a typical style for Art History papers).