Autoepistemic Logic
The autoepistemic logic is a formal logic for the representation and reasoning of knowledge about knowledge. While propositional logic can only express facts, autoepistemic logic can express knowledge and lack of knowledge about facts. The stable model semantics, which is used to give a semantics to logic programming with negation as failure, can be seen as a simplified form of autoepistemic logic. (http://en.wikipedia.org/wiki/Autoepistemic_logic)
Autoepistemic Logic and Introspective Circumscription 1994
Michael Gelfond, Vladimir Lifschitz, Halina Przymusinska and Grigori Schwarz, In Theoretical Aspects of Reasoning about Knowledge: Proceedings Fifth Conf., Fagin, Ronald (Eds.), pp. 197-207 1994.
Extended Logic Programs as Autoepistemic Theories 1993
Vladimir Lifschitz and Grigori Schwarz, In Logic Programming and Non-monotonic Reasoning: Proceedings of the Second Int'l Workshop, Pereira, Luis Moniz and Nerode, Anil (Eds.), pp. 101-114 1993.