U. O'Reilly. Proceedings of the 1998 IEEE World Congress on
Computational Intelligence, page 306--311. Anchorage, Alaska, USA, IEEE Press, (5-9 May 1998)
J. Kubica, and E. Rieffel. GECCO 2002: Proceedings of the Genetic and
Evolutionary Computation Conference, page 804--811. New York, Morgan Kaufmann Publishers, (9-13 July 2002)