Yuki Watanabe Tomoko Kojiri Toyohide Watanabe Organization of Solution Knowledge Graph from Collaborative Learning Records. 564-571 2009 KES (2) http://dx.doi.org/10.1007/978-3-642-04592-9_70 conf/kes/2009-2 db/conf/kes/kes2009-2.html#WatanabeKW09