West, R. M. 1971. Deciduous dentition of the Early Tertiary Phenacodontidae (Condylarthra, Mammalia). American Museum Novitates. (2461) pp. 1-37.
Whitmore, F. C. 1953. Cranial morphology of some Oligocene Artiodactyla. U. S. Geol. Surv. Prof. Paper. Vol. 243H, pp. 117-160.