C. Clack, J. Farringdon, P. Lidwell, и T. Yu. Research Note, RN/96/48. University College London, Computer Science, Gower Street, London, WC1E 6BT, UK, (июня 1996)
R. Salustowicz, и J. Schmidhuber. Proceedings of the Genetic and Evolutionary
Computation Conference, 2, стр. 1184--1191. Orlando, Florida, USA, Morgan Kaufmann, (13-17 July 1999)