Default Knowledge in Logic Programs with Uncertainty.

Yann Loyer Umberto Straccia Default Knowledge in Logic Programs with Uncertainty. 466-480 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2916&spage=466 2003 conf/iclp/2003 ICLP db/conf/iclp/iclp2003.html#LoyerS03