1. Needham, J. Biol. Rev. 8, 180–233 (1933).
2. Gerhart, J. & Kirschner, M. Cells, Embryos, and Evolution (Blackwell Science, Malden, Massachusetts, 1997).
3. Hartwell, L.H., Hopfield, J.J., Leibler, S. & Murray, A.W. Nature 402, C47–C52 (1999).
4. Schlosser, G. Theory Biosci. 121, 1–80 (2002).
5. Schlosser, G. & Wagner, G.P. (eds.) Modularity in Development and Evolution (University of Chicago Press, Chicago, Illinois, 2004).