1. “I lied about the trees” or defaults and definitions in knowledge representation;Brachman;The AI Magazine,1985
2. Basic conditional logic;Chellas;J. Philos. Logic,1975
3. The mathematics of non-monotonic reasoning;Davis;Artificial Intelligence,1980
4. A propositional logic for natural kinds;Delgrande,1986
5. An approach to default reasoning based on a first-order conditional logic;Delgrande,1987