A. Hill and S. Ward. Origin of the Hominidae: the record of African large hominoid evolution between 14 My and 4 My. Am. J. Phys. Anthropol., volume 31, issue 9, pages 49-83, 1988. S. Ward and A. Hill. Pliocene hominid partial mandible from Tabarin, Baringo, Kenya. American Journal of Physical Anthropology, Wiley, volume 72, issue 1, pages 21-37, January 1987. A. Hill. Early hominid from Baringo, Kenya. Nature, Nature, volume 315, pages 222-224, May 1985.