D. Wedge, S. Gaskell, S. Hubbard, D. Kell, K. Lau, and C. Eyers. GECCO '07: Proceedings of the 9th annual conference on
Genetic and evolutionary computation, 2, page 2219--2225. London, ACM Press, (7-11 July 2007)
E. Jordaan, J. den Doelder, and G. Smits. Parallel Problem Solving from Nature - PPSN IX, volume 4193 of LNCS, page 322--331. Reykjavik, Iceland, Springer-Verlag, (9-13 September 2006)