Recently, I have found this very interesting and useful research tool: a bibliography for the study of medieval cultural centre from Cluny. From my own information, it is unique because it deals with a cultural centre and not an author, a masterpiece or an idea. Another argument for its usefulness is its range: from 1498 until today. It is very easy to use, all references being complete.
Link: Bibliotheca Cluniacensis novissima. Cluny-Bibliographie, 1498-2007