R. Peters, J. Broekens, and M. Neerincx. Proceedings of the 22Nd International Conference on Intelligent User Interfaces, page 401--405. New York, NY, USA, ACM, (2017)
T. Käser, S. Klingler, A. Schwing, and M. Gross. volume 8474 of Lecture Notes in Computer Science, page 188--198. Springer International Publishing, (2014)
J. Gu, Y. Wang, and N. Heffernan. Intelligent Tutoring Systems, volume 8474 of Lecture Notes in Computer Science, Springer International Publishing, (2014)