Mahat Khelfallah Aïcha Mokhtari Ramification in the Normative Method of Causality. 704-713 2001 conf/ecsqaru/2001 ECSQARU http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2143&spage=0704 db/conf/ecsqaru/ecsqaru2001.html#KhelfallahM01