1. Cavalli-Sforza, L. L., Menozzi, P. & Piazza, A. History and Geography of Human Genes (Princeton Univ. Press, 1994).
2. Roychoudhury, A. K. & Nei, M. Human Polymorphic Genes: World Distribution (Oxford Univ. Press, 1988).
3. Haldane, J. B. S. The rate of mutation of human genes. Hereditas 35 (Suppl. 1), 267–272 (1949).
4. Fisher, R. The wave of advance of advantageous genes. Ann. Eugen. 7, 355–369 (1937). A classic paper that establishes a reaction–diffusion model for the spread of an advantageous allele and uses it to calculate the speed of the expanding wave of advance.
5. Roberts, D. F. Human pigmentation: its geographical and racial distribution and biological significance. J. Soc. Cosmet. Chem. 28, 329–342 (1977).