Cope, E.D. (1888)
Systematic catalogue of the species of Vertebrata found in the beds of the Permian epoch in North America, with notes and descriptions. Transactions of the American Philosophical Society, 16, 285–297
Hay, O.P. (1902)
Bibliography and catalogue of the fossil Vertebrata of North America. Bulletin of the United States Geological and Geographical Survey of the Territories, 179, 1–868