*Jacobs, Louis, Scott, Katherine Marie. ''Evolution of Tertiary Mammals of North America: Terrestrial Carnivores, Ungulates, and Ungulate-like Mammals''; Cambridge University Press, 1998 | *Jacobs, Louis, Scott, Katherine Marie. ''Evolution of Tertiary Mammals of North America: Terrestrial Carnivores, Ungulates, and Ungulate-like Mammals''; Cambridge University Press, 1998 |