Cope, Edward Drinker (August 1873). "The Monster of Mammoth Buttes". In Thompson, Robert Ellis; Newton, William Wilberforce; Kendall, Otis H. (eds.). Penn Monthly. University Press Company. pp. 521–34.
Prothero, Donald R. (2002). Horns, tusks, and flippers : the evolution of hoofed mammals. Schoch, Robert M. Baltimore: Johns Hopkins University Press. pp. 11–12. ISBN0801871352. OCLC49681344.