P. Lessel, M. Müller, and A. Krüger. Proceedings of the 33rd Annual ACM Conference Extended Abstracts on Human Factors in Computing Systems (CHI EA '15), Seoul, Republic of Korea, page 1809--1814. New York, ACM, (2015)
P. Joubert, and S. Roodt. Entertainment Computing -- ICEC 2009: 8th International Conference, Paris, France, volume 5709 of Lecture Notes in Computer Science, Springer, Berlin, (2009)