Rainer Malaka Kerstin Schneider Ursula Kretschmer Stage-Based Augmented Edutainment. 54-65 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3031&spage=54 2004 conf/sg/2004 Smart Graphics db/conf/sg/sg2004.html#MalakaSK04