Joaquín García-Alfaro Frédéric Cuppens Nora Cuppens-Boulahia Management of Exceptions on Access Control Policies. 97-108 2007 SEC http://dx.doi.org/10.1007/978-0-387-72367-9_9 conf/sec/2007 db/conf/sec/sec2007.html#Garcia-AlfaroCC07