Enrico Pontelli Marcello Balduccini F. Bermudez Non-monotonic Reasoning on Beowulf Platforms. 37-57 2003 conf/padl/2003 PADL http://link.springer.de/link/service/series/0558/bibs/2562/25620037.htm db/conf/padl/padl2003.html#PontelliBB03