Isaac Agudo M. Carmen Fernández Gago Javier Lopez Delegating Privileges over Finite Resources: A Quota Based Delegation Approach. 302-315 2008 Formal Aspects in Security and Trust http://dx.doi.org/10.1007/978-3-642-01465-9_20 conf/ifip1-7/2008 db/conf/ifip1-7/fast2008.html#AgudoGL08