1. Bernstein, P., Hadzilacos, V. and Goodman, N., 1987, Concurrency Control and Recovery in Database Systems, Addison-Wesley.
2. Brown, A. L. and Mantha, S., 1991, ?Preferences as Normative Knowledge: Towards Declarative Obligations?, in: Meyer, J.-J. Ch. and Wieringa, R.J. (eds.), Proc. First International Workshop on Deontic Logic in Computer Science (DEON'91), 142?163.
3. Carmo, J. and Sernadas, A., 1991, ?Formal Techniques for Systems Specification and Verification?, Information Systems 16, 245?272.
4. Castilho, J. M. V., Casanova, M. A. and Furtado, A. L., 1982, ?A Temporal Framework for Information Systems Specification?, Proc. 8th VLDB Conference, 280?291.
5. Carmo, J. and Jones, A. J. I., 1994, ?Deontic Database Constraints and the Characterisation of Recovery?, in Jones, A. J. I. and Sergot, M. (eds.) DEON'94: Second International Workshop on Deontic Logic in Computer Science, Tano Forlag, Oslo, Norway.