1. Towards a theory of declarative knowledge;Apt,1988
2. Default reasoning using classical logic;Ben-Eliyahu;Artificial Intelligence,1996
3. Minimalism subsumes default logic and circumscription in stratified logic programming;Bidoit,1987
4. Formalizing nonmonotonic reasoning systems;Etherington;Artificial Intelligence,1987
5. The justification of negation as failure;Fine;Logic, Methodology and Philosophy of Science,1989