Estes, R. & Berberian, P. (1970)
Paleoecology of a Late Cretaceous vertebrate community from Montana. Breviora, 343, 1–35

Estes, R. & Berberian, P. & Meszoely, C. (1969)
Lower vertebrates from the Late Cretaceous Hell Creek Formation, McCone County, Montana. Breviora, 337, 1–33