1. P.A. Bonatti, M.L. Sapino, and V.S Subrahmanian. Merging heterogeneous security orderings. In Martella Bertino, Kurth and Montolivo, editors, Computer Security — ESORICS96, LNCS1146, pages 183–197. Springer-Verlag, 1996.
2. S. Castano, M. Fugini, G. Martella, and P. Samarati. Database Security. Addison-Wesley, 1994.
3. Oracle Corporation. Oracle Version 7, Chapters 6 & 7.
4. S. di Virmercati and P. Samarati. An authorization model for federated systems. In Martella Bertino, Kurth and Montolivo, editors, ESORICS96, LNCS 1146, pages 99–117. Springer-Verlag, 1996.
5. L. Hua and S. Osborn. Modeling unix access control with a role graph. In Proc. International Conference on Computers and Information, June 1998.