Gray Squirrel (Sciurus carolinensis) Scratching from “We Watch Squirrels” by Ada and Frank Graham - PC-71, ©1985, Box: 5, Folder: 37, item: 3. 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/310646 Accessed January 21, 2025.