1. Propositional temporal interval logic is PSPACE-complete;Aaby,1988
2. An axiomatization of Lamport's Temporal Logic of Actions;Abadi,1990
3. An axiomatization of Lamport's Temporal Logic of Actions;Abadi,1990
4. Maintaining knowledge about temporal intervals;Allen;Comm. ACM,1983
5. Defining liveness;Alpern,1985