1. Oxnard, C. E. (1973). Form and Pattern in Human Evolution. Chicago, IL: University of Chicago Press
2. Tooth measurements and the rejection of the taxon “Homo habilis;Brace;Yrbk. Phys. Anthropol.,1973
3. Mayr, E. and Ashlock, P. D. (1991). Principles of Systematic Zoology. New York, NY: McGraw-Hill
4. Multivariate Craniometric Variation in Chimpanzees
5. Groves, C. P. (1986). Systematics of the great apes. In: Comparative Primate Biology. Vol. 1. Systematics, Evolution, & Anatomy, ed. D. R. Swindler and J. Erwin. New York: Alan R. Liss. pp. 187–217