N. Koenig, and A. Howard. 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566), 3, page 2149-2154 vol.3. (September 2004)
S. van Houten, G. Bekebrede, R. Scalzo, A. Moeis, N. Bowden, and I. Mayer. ISAGA'04: Proc. 35th Conf. of the Int'l Simulation
and Gaming Association. Bridging the Gap: Transforming Knowledge
into Action through Gaming and Simulation, page 134--143. Munich, Germany, Sagsaga, (2004)