S. Finney, {. Gardiol, {. Kaelbling, and T. Oates. Proceedings of the Eighteenth International Conference on Uncertainty in Artificial Intelligence (UAI-02), page 154--161. Edmonton, Alberta, Canada, (August 2002)
{. Kaelbling, T. Oates, {. Gardiol, and S. Finney. Working Notes (SS-01-05) of the AAAI Stanford Spring Symposium on Learning Grounded Representations, page 31--36. Stanford, CA, USA, AAAI Press, (March 2001)