Chunxiao Ye Zhongfu Wu Jiang Zhong Yong Feng Revocation in an Attribute-Based Delegation Model. 171-172 2008 NAS http://doi.ieeecomputersociety.org/10.1109/NAS.2008.39 conf/iwnas/2008 db/conf/iwnas/nas2008.html#YeWZF08