Notes
- . Kirtley F.Mather, “Geologic Factors in Organic EvolutionOhio Journal of Science 24 (1924): 117–45.
- . Robert Ardrey, African Genesis (New York: Atheneum Publishers, 1961).
- . W. M. Wheeler, The Social Insects, Their Origin and Evolution (New York: Harcourt, Brace & Co., 1928).