Orkunt Sabuncu Ferda Nur Alpaslan Varol Akman Using Criticalities as a Heuristic for Answer Set Programming. 234-246 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2923&spage=234 2004 conf/lpnmr/2004 LPNMR db/conf/lpnmr/lpnmr2004.html#SabuncuAA04