Haipeng Guo Prashanth R. Boddhireddy William H. Hsu An ACO Algorithm for the Most Probable Explanation Problem. 778-790 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3339&spage=778 2004 conf/ausai/2004 Australian Conference on Artificial Intelligence db/conf/ausai/ausai2004.html#GuoBH04