Silvio do Lago Pereira Leliane Nunes de Barros Planning with Abduction: A Logical Framework to Explore Extensions to Classical Planning. 62-72 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3171&spage=62 2004 conf/sbia/2004 SBIA db/conf/sbia/sbia2004.html#PereiraB04