Elisa Bertino Sushil Jajodia Pierangela Samarati A Flexible Authorization Mechanism for Relational Data Management Systems. 101-140 1999 17 ACM Trans. Inf. Syst. 2 http://doi.acm.org/10.1145/306686.306687 db/journals/tois/tois17.html#BertinoJS99