Grizzly Bear, Polar Bear, Black Bear from “Bears in the Wild” by Ada & Frank Graham - NC-4, ©1981, Box: 5, Folder: 17, item: 1. Natural History Art and Illustration by D. D. Tyler, MS 337. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/310553 Accessed June 15, 2025.