Cope, E.D. (1874)
Review of the Vertebrata of the Cretaceous period found west of the Mississippi River. Sec. I. On the mutual relations of the Cretaceous and Tertiary formations of the West. Sec. II. List of species of Vertebrata from the Cretaceous formations. Bulletin of the United States Geological and Geographical Survey of the Territories, 1(2): 3–48
Cope, E.D. (1875)
The Vertebrata of the Cretaceous formations of the West. Report of the United States Geological Survey of the Territories, 2: 303 p., 67 pl.