A. Kordon, F. Castillo, G. Smits, and M. Kotanchek. Genetic Programming Theory and Practice III, volume 9 of Genetic Programming, chapter 16, Springer, Ann Arbor, (12-14 May 2005)
F. Castillo, A. Kordon, and G. Smits. Genetic Programming Theory and Practice IV, volume 5 of Genetic and Evolutionary Computation, chapter 2, Springer, Ann Arbor, (11-13 May 2006)