Authoritative articles that help situate your topic (or source) within a broader context, and give you a sense of the state of current research.
Regularly updated annotated bibliographies. University of Chicago Library subscribes to many sections of Oxford Bibliographies Online such as African Studies, Anthropology, Art History, Atlantic History, Buddhism, Childhood Studies, Chinese Studies, Cinema and Media Studies, Classics, Environmental Science, Geography, International Law, International Relations, Islamic Studies, Latin American Studies, Medieval Studies, Military History, Music, Political Science, Renaissance and Reformation, Social Work, and Sociology.