Robert G. M. Hausmann Brett van de Sande Kurt VanLehn Shall We Explain? Augmenting Learning from Intelligent Tutoring Systems and Peer Collaboration. 636-645 2008 Intelligent Tutoring Systems http://dx.doi.org/10.1007/978-3-540-69132-7_66 conf/its/2008 db/conf/its/its2008.html#HausmannSV08