Meriam Ben-Ghorbel-Talbi Frédéric Cuppens Nora Cuppens-Boulahia Adel Bouhoula An Extended Role-Based Access Control Model for Delegating Obligations. 127-137 2009 TrustBus http://dx.doi.org/10.1007/978-3-642-03748-1_13 conf/trustbus/2009 db/conf/trustbus/trustbus2009.html#Ben-Ghorbel-TalbiCCB09