Earliest man and environments in the Lake Rudolf Basin : stratigraphy, paleoecology, and evolution; [proceedings of a workshop-symposium held in East Africa, Sept. 9 - 19, 1975, sponsored by the Wenner-Gren Foundation for Anthropological Research, N. Y., and by the National Geographic Society, Washington, D. C.] - Coppens, Yves (University of Chicago Press, 1976)