U. Thieme and F. Becker, eds: Allgemeines Lexikon der bildenden Künstler von der Antike bis zur Gegenwart, 37 vols (Leipzig, 1907–50) [see also Meissner above]
F. O’Donoghue and H. M. Hake: Catalogue of Engraved British Portraits Preserved in the Department of Prints and Drawings in the British Museum, 6 vols (London, 1908–25)