Camp, C. L., & Welles, S. P. (1956). Triassic dicynodont reptiles. Part I. The north american genus placerias, by C. L. Camp and S. P. Welles. Part II. Triassic dicynodonts compared by C. L. Camp. University of California.

Camp, Charles L., and Samuel Paul Welles. Triassic Dicynodont Reptiles. Part I. The North American Genus Placerias, by C. L. Camp and S. P. Welles. Part II. Triassic Dicynodonts Compared by C. L. Camp. Berkeley: University of California, 1956.

Camp, Charles L., and Samuel Paul Welles. Triassic Dicynodont Reptiles. Part I. The North American Genus Placerias, by C. L. Camp and S. P. Welles. Part II. Triassic Dicynodonts Compared by C. L. Camp. University of California, 1956.