R. Poli, and N. McPhee. Genetic Programming, Proceedings of EuroGP'2001, volume 2038 of LNCS, page 126--142. Lake Como, Italy, Springer-Verlag, (18-20 April 2001)
H. Majeed, and C. Ryan. GECCO 2006: Proceedings of the 8th annual conference
on Genetic and evolutionary computation, 1, page 847--854. Seattle, Washington, USA, ACM Press, (8-12 July 2006)
R. Aler, D. Borrajo, and P. Isasi. Proceedings of the 2001 Congress on Evolutionary
Computation CEC2001, page 1220--1227. COEX, World Trade Center, 159 Samseong-dong,
Gangnam-gu, Seoul, Korea, IEEE Press, (27-30 May 2001)