United States of America, Ass. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed June 2019.
The Donkey. Government of Alberta: Agriculture and Rural Development, 1990. Archived 15 August 2011.
Sandra L. Olsen (editor) (1996). Horses Through Time. Boulder, Colorado: Roberts Rinehart Publishers for Carnegie Museum of Natural History. ISBN9781570980602; cited at Donkey. Lexington, Kentucky: The International Museum of the Horse. Archived 12 August 2011.
Dent, Anthony (1972) Donkey: The Story of the Ass from East to West London: Harrap ISBN9780245599323 "There is no breed of ass that can be regarded as a specific and original American development", cited at The Donkey Government of Alberta: Agriculture and Rural Development, 1990. Archived 15 August 2011.
All About Donkeys! The American Donkey and Mule Society. Archived 14 August 2011.
About donkeys. Canadian Donkey and Mule Association. Archived 16 January 2012.