↑W. D. Matthew. (1909.) "The Carnivora and Insectivora of the Bridger Basin, middle Eocene." Memoirs of the American Museum of Natural History 9:289-567
↑M. R. Dawson, R. K. Stucky, L. Krishtalka and C. C. Black. (1986.) "Machaeroides simpsoni, new species, oldest known sabertooth creodont (Mammalia), of the Lost Cabin Eocene." Contributions to Geology, University of Wyoming, Special Paper 3:177-182