J. Koza, L. Jones, M. Keane, and M. Streeter. Genetic Programming Theory and Practice II, chapter 8, Springer, Ann Arbor, pages missing?.(13-15 May 2004)
M. Streeter, and L. Becker. 2001 Genetic and Evolutionary Computation Conference
Late Breaking Papers, page 398--404. San Francisco, California, USA, (9-11 July 2001)