D. Cram, A. Kröner, and A. Mille. Workshops Proceedings of the 5th International Conference on Intelligent Environments, volume 4 of Ambient Intelligence and Smart Environments, page 45--50. Amsterdam, IOS Press, (2009)
B. Gernhardt, T. Vogel, M. Givehchi, L. Wang, and M. Hemmje. Proceedings of the ASME 2016 International Manufacturing Science and Engineering Conference, MSEC2016, June 27--July 1, 2016, Blacksburg, Virginia, USA, 2, page V002T04A013:1--10. New York, NY, American Society of Mechanical Engineers (ASME), (2016)
M. Beetz, M. Buss, and D. Wollherr. KI 2007: Advances in Artificial Intelligence, volume 4667 of Lecture Notes in Artificial Intelligence, Springer, Berlin, (2007)