E. Burke, S. Gustafson, G. Kendall, and N. Krasnogor. Parallel Problem Solving from Nature - PPSN VII, 2439, page 341--350. Granada, Spain, Springer-Verlag, (7-11 September 2002)
E. Burke, S. Gustafson, and G. Kendall. GECCO 2002: Proceedings of the Genetic and
Evolutionary Computation Conference, page 716--723. New York, Morgan Kaufmann Publishers, (9-13 July 2002)
W. Banzhaf, and A. Leier. Genetic Programming Theory and Practice III, volume 9 of Genetic Programming, chapter 14, Springer, Ann Arbor, (12-14 May 2005)