Ulrich Endriss Paolo Mancarella Fariba Sadri Giacomo Terreni Francesca Toni Abductive Logic Programming with CIFF: System Description. 680-684 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3229&spage=680 2004 conf/jelia/2004 JELIA db/conf/jelia/jelia2004.html#EndrissMSTT04a