Babak Sadighi Firozabadi Marek J. Sergot Anna Cinzia Squicciarini Elisa Bertino A Framework for Contractual Resource Sharing in Coalitions. 117-126 2004 conf/policy/2004 POLICY http://csdl.computer.org/comp/proceedings/policy/2004/2141/00/21410117abs.htm db/conf/policy/policy2004.html#FirozabadiSSB04