Miroslav Minovic Milos Milovanovic Dusan Starcevic Mladjan Jovanovic Knowledge Modeling for Educational Games. 156-165 2009 WSKS (1) http://dx.doi.org/10.1007/978-3-642-04754-1_17 conf/wsks/2009-1 db/conf/wsks/wsks2009-1.html#MinovicMSJ09