1. Levin, B. R. in The Evolution of Sex: an Examination of Current Ideas (eds Michod, R. E. & Levin, B. R.) 194–211 (Sinauer, Sunderland, 1988).
2. Weismann, A. Nature 36, 607–609 (1887).
3. Lloyd, D. G. Evol. Biol. 13, 69–91 (1980).
4. Muller, H. J. in Genetics, Paleontology and Evolution (eds Jepsen, G. L., Mayr, E. & Simpson, G. G.) 421–447 (Princeton University Press, 1949).
5. Maynard Smith, J. The Evolution of Sex (Cambridge University Press, 1978).