C. Jacob, and I. Burleigh. Genetic Programming Theory and Practice III, volume 9 of Genetic Programming, chapter 13, Springer, Ann Arbor, (12-14 May 2005)
F. Archetti, S. Lanzeni, E. Messina, and L. Vanneschi. GECCO 2006: Proceedings of the 8th annual conference
on Genetic and evolutionary computation, 1, page 255--262. Seattle, Washington, USA, ACM Press, (8-12 July 2006)