Yousri El Fattah Potential Causality in Mixed Initiative Planning. 689-698 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3029&spage=689 2004 conf/ieaaie/2004 IEA/AIE db/conf/ieaaie/ieaaie2004.html#Fattah04