J. Shin, M. Kang, B. McKay, X. Nguyen, T. Hoang, N. Mori, and D. Essam. Proceedings of the 10th European Conference on Genetic
Programming, volume 4445 of Lecture Notes in Computer Science, page 251--260. Valencia, Spain, Springer, (11 - 13 April 2007)
B. McKay, B. Lennox, M. Willis, G. Barton, and G. Montague. UKACC International Connference on Control'96, 2, page 734--739. Exeter, UK, IEE, (2-5 September 1996)Conference publication No. 427.
B. McKay, M. Willis, G. Montague, and G. Barton. Genetic Programming 1996: Proceedings of the First
Annual Conference, page 157--165. Stanford University, CA, USA, MIT Press, (28--31 July 1996)