J. Decraene, G. Mitchell, B. McMullin, and C. Kelly. Proceedings of the 10th European Conference on Genetic
Programming, volume 4445 of Lecture Notes in Computer Science, page 361--370. Valencia, Spain, Springer, (11 - 13 April 2007)
N. McPhee, N. Hopper, and M. Reierson. Genetic Programming 1998: Proceedings of the Third
Annual Conference, page 241. University of Wisconsin, Madison, Wisconsin, USA, Morgan Kaufmann, (22-25 July 1998)
N. McPhee, N. Hopper, and M. Reierson. Genetic Programming 1998: Proceedings of the Third
Annual Conference, page 232--240. University of Wisconsin, Madison, Wisconsin, USA, Morgan Kaufmann, (22-25 July 1998)