M. Hemberg, U. O'Reilly, and P. Nordin. 2001 Genetic and Evolutionary Computation Conference
Late Breaking Papers, page 160--167. San Francisco, California, USA, (9-11 July 2001)
U. O'Reilly, and G. Ramachandran. Proceedings of the Sixth International Conference on
Artificial Life, page 443--447. University of California, Los Angeles, MIT Press, (26-29 June 1998)