Tomoya Enokido Makoto Takizawa Synchronization of Transactions to Prevent Illegal Information Flow in a Role-Based Access Control Model. 779-786 2008 AINA http://doi.ieeecomputersociety.org/10.1109/AINA.2008.145 conf/aina/2008 db/conf/aina/aina2008.html#EnokidoT08