(10) Crown Folio - German Ramphastiden ["Monographie der Ramphastiden"], Box: 16, Folder: 51. Sauer's Gouldiana Research about John Gould and other papers, MS 304. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/205878 Accessed January 28, 2025.