M. Makatchev, P. Jordan, and K. VanLehn. Intelligent Tutoring Systems, volume 3220 of Lecture Notes in Computer Science, page 699-709. Springer, (2004)
P. Jordan, M. Makatchev, and K. VanLehn. Intelligent Tutoring Systems, volume 3220 of Lecture Notes in Computer Science, page 346-357. Springer, (2004)