1. S. Wolfram: Rev. Mod. Phys. 55, 601 (1983)
2. N.H. Packard, S. Wolfram: J. Stat. Phys. 38, 901 (1986)
3. S. Wolfram: Theory and Applications of Cellular Automata (World Scientific, Singapore 1986)
4. G. Weisbuch: Dynamique des systèmes complexes (Editions du CNRS, Paris 1989); English translation: Complex System Dynamics (Addison-Wesley, New York 1991); for programming techniques see also D. Stauffer: Computers in Physics, Jan/Feb 1991, p. 62, Ref. [9.51b], and R.W. Gerling, D. Stauffer: in preparation
5. G.Y. Vichniac: Physica D 10, 96 (1984)