1. Weidenreich, F. Palaeont. sin. No. 127, 1–485 (1943).
2. Jacob, T. in Paleoanthropology (ed. Tuttle, R.) (Mouton, 1975).
3. Howells, W. W. Evolution of the Genus Homo (Addison-Wesley, Massachusetts, 1973).
4. Leakey, R. & Walker, A. Nature 261, 572–574 (1976).
5. Leakey, L. S. B. Nature 189, 649–650 (1961).