Johan Wittocx Joost Vennekens Maarten Mariën Marc Denecker Maurice Bruynooghe Predicate Introduction Under Stable and Well-Founded Semantics. 242-256 2006 conf/iclp/2006 ICLP http://dx.doi.org/10.1007/11799573_19 db/conf/iclp/iclp2006.html#WittocxVMDB06