Frit's Lugt's survey of collectors’ marks contains a wealth of information about print and drawing collectors and their collections. It is the most important manual for specialists of drawings and prints to trace the provenance of works on paper, by means of recorded collectors’ marks, written or stamped. Besides collectors’ marks and institutional stamps, one finds also marks of dealers, mounters and editors as well as studio stamps. It is available in an online database as well as in print in the library.