M. Beetz, M. Buss, and D. Wollherr. KI 2007: Advances in Artificial Intelligence, volume 4667 of Lecture Notes in Artificial Intelligence, Springer, Berlin, (2007)
L. Chen, J. Hoey, C. Nugent, D. Cook, and Z. Yu. IEEE Transactions on Systems, Man, and Cybernetics, Part C: Applications and Reviews, 42 (6):
790-808(November 2012)