Michael Gelfond Marcello Balduccini Joel Galloway Diagnosing Physical Systems in A-Prolog. 213-225 2001 conf/lpnmr/2001 LPNMR http://link.springer.de/link/service/series/0558/bibs/2173/21730213.htm db/conf/lpnmr/lpnmr2001.html#GelfondBG01