Regina Stathacopoulou Maria Grigoriadou Maria Samarakou George D. Magoulas Using Simulated Students for Machine Learning. 889-891 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3220&spage=889 2004 conf/its/2004 Intelligent Tutoring Systems db/conf/its/its2004.html#StathacopoulouGSM04