Griesemer JR. 2000. Reproduction and the Reduction of Genetics. The Concept of the Gene in Development and Evolution: Historical and Epistemological Perspectives. Cambridge University Press:240-285 Griesemer JR and MJ Wade. 2000. Populational Heritability: Extending Punnett Square Concepts to Evolution at the Metapopulation Level. Biology and Philosophy. 15:1-17 Wade MJ and JR Griesemer. 1998. Populational heritability: Empirical Studies of Evolution in Metapopulations. American Naturalist. 151:135-147