Paul de Vrieze Patrick van Bommel Theo P. van der Weide A Generic Adaptivity Model in Adaptive Hypermedia. 344-347 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3137&spage=344 2004 conf/ah/2004 AH db/conf/ah/ah2004.html#VriezeBW04