R. Poli, and W. Langdon. Genetic Algorithms: Proceedings of the Seventh
International Conference, page 18--25. Michigan State University, East Lansing, MI, USA, Morgan Kaufmann, (19-23 July 1997)
R. Poli, W. Langdon, and U. O'Reilly. Genetic Programming 1998: Proceedings of the Third
Annual Conference, page 284--292. University of Wisconsin, Madison, Wisconsin, USA, Morgan Kaufmann, (22-25 July 1998)
P. Martin, and R. Poli. Technical Report, CSM-357. Department of Computer Science, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK., (24th January 2002)
R. Poli, and W. Langdon. GECCO 2005: Proceedings of the 2005 conference on
Genetic and evolutionary computation, 2, page 1777--1778. Washington DC, USA, ACM Press, (25-29 June 2005)