J. Väyrynen, and T. Honkela. Proceedings of the STeP'2004 Cognition + Cybernetics Symposium, page 173--185. Finnish Artificial Intelligence Society, (2004)
T. Honkela, A. Hyvärinen, and J. Väyrynen. A72. Helsinki University of Technology, Laboratory of Computer and Information Science, Espoo, Finland, (2003)
J. Väyrynen, and T. Lindh-Knuutila. Proceedings of the The Ninth Scandinavian Conference on Artificial Intelligence (SCAI 2006), 22, page 101--105. Finnish Artificial Intelligence Society, (2006)