1. Modal nonmonotonic logics demodalized;Bochman;Annals of Mathematics and Artificial Intelligence,1993
2. Basic modal logic;Bull,1984
3. The pure logic of necessitation;Fitting;J of Logic and Computation,1992
4. Investigations in Modal and Tense Logics;Gabbay,1976
5. Negation as inconsistency;Gabbay;J of Logic Programming,1986