Billy Ireland Cartoon Library & Museum biographical files
Brockhaus and Efron Encyclopedic Dictionary
Small Brockhaus and Efron Encyclopedic Dictionary
WikiProject PCC Wikidata Pilot/Frick Art Reference Library
The Stuttgart Database of Scientific Illustrators 1450–1950
Spotprent in zwart-wit, nr. 71 uit de serie 'Les Metamorphoses du Jour'
artist list of the National Museum of Sweden
Faceted Application of Subject Terminology