1. S. Abiteboul, M. Vardi, and V. Vianu. Fixpoint logic, relational machines and computational complexity. In Structure in Complexity Theory, 1992.
2. C. Baral. Reasoning about actions: non-deterministic effects, constraints and qualification. In Proc. of IJCAI, Montreal, 1995.
3. C. Baral and M. Gelfond. Representing concurrent actions in extended logic programs. In Bertram Fronhofer, editor, Theoretical Approaches to Dynamic Worlds. (to appear). Preliminary version appeared in IJCAI 93.
4. C. Basal, M. Gelfond, and A. Provetti. Representing Actions: Laws, Observations and Hypothesis. Journal of Logic Programming (to appear), 1997.
5. C. Baral and J. Lobo. Formal characterization of active databases. In International Workshop on Logic in Databases, 1996.