Heffner, Rickye, Comparative Study of Sound Localization in Mammals, #4916-x706 (original grant re-negotiated), February 31, 1981, Box: 42, Folder: 20. University of Kansas Schiefelbusch Institute for Life Span Studies records, RG 35. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/454044 Accessed July 10, 2025.