Indrakshi Ray Manachai Toahchoodee A Spatio-temporal Access Control Model Supporting Delegation for Pervasive Computing Applications. 48-58 2008 TrustBus http://dx.doi.org/10.1007/978-3-540-85735-8_6 conf/trustbus/2008 db/conf/trustbus/trustbus2008.html#RayT08