U. S. Department of Agriculture Bureau of Biological Survey, North American Fauna No. 47 (August 21, 1924) : Revision of the American Pikas (Genus Ochotona).
Softcover, Washington, D. C. Government Printing Office, 1924. Good with no dust jacket.
Softcover, Washington, D. C. Government Printing Office, 1924. Good with no dust jacket.