Philippe Fournier-Viger Roger Nkambou André Mayers Evaluating Spatial Knowledge through Problem-Solving in Virtual Learning Environments. 15-26 2008 EC-TEL http://dx.doi.org/10.1007/978-3-540-87605-2_2 conf/ectel/2008 db/conf/ectel/ectel2008.html#Fournier-VigerNM08