L. von Ahn, и L. Dabbish. CHI '04: Proceedings of the SIGCHI conference on Human factors in computing systems, стр. 319--326. New York, NY, USA, ACM Press, (2004)
J. McCarthy. Proceedings of the Teddington Conference on the Mechanization of Thought Processes, стр. 75--91. London, Her Majesty's Stationary Office, (1959)
L. Steels. Artificial Life V: Proceeding of the Fifth International Workshop on the Synthesis and Simulation of Living Systems, стр. 179--184. Cambridge, MA, The MIT Press, (1996)