Jürgen Dix Luís Moniz Pereira Teodor C. Przymusinski Non-Monotonic Extensions of Logic Programming, NMELP '96, Bad Honnef, Germany, September 5-6, 1996, Selected Papers NMELP Lecture Notes in Computer Science 1216 Springer 1997 3-540-62843-6 db/conf/nmelp/nmelp96.html