R. Calegari, G. Ciatto, J. Dellaluce, and A. Omicini. WOA 2019 -- 20th Workshop ``From Objects to Agents'', volume 2404 of CEUR Workshop Proceedings, Sun SITE Central Europe, RWTH Aachen University, (2019)
T. Yu, and J. Miller. Genetic Programming, Proceedings of EuroGP'2001, volume 2038 of LNCS, page 204--217. Lake Como, Italy, Springer-Verlag, (18-20 April 2001)