Calkins, Earnest Elmo. Care and Feeding of Hobby Horses. New York: Leisure League of America, 1934

Calkins, Earnest Elmo. Care and Feeding of Hobby Horses. New York: Leisure League of America, 1934, Volume: Gilbert B119. Robert L. Gilbert First Issues collection, Gilbert. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/525424 Accessed December 27, 2025.