1. For a general presentation of the field and references to original papers see: G. Nicolis and I. Prigogine, Selforganization in non-equilibrium systems, Wiley, New York (1977).
2. See the papers by Horsthemke, Lefever, Sancho and San Miguel in: Stochastic nonlinear systems, Springer Series in synergetics 8 (1981).
3. R. Garay and R. Lefever, J. Theor. Biol. 73, 417 (1978).
4. R. Lefever and R. Garay, in: Biomathematics and cell kinetics, Elsevier, Amsterdam (1978)
5. R. A. Fisher, Ann. of Eugenics 7, 355 (1937)