Staatliche Museen Preussicher Kulturbesitz Nationalgalerie (City Museums of the Prussian Cultural Seat National Gallery), Berlin, 1968, Box: 4, Folder: 127. Edith Krull collection, MS 345. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/375798 Accessed December 26, 2024.