Yuqing Sun Bin Gong Xiangxu Meng Zongkai Lin Active Authorization Management for Multi-domain Cooperation. 162-167 2007 CSCWD http://dx.doi.org/10.1109/CSCWD.2007.4281428 conf/cscwd/2007 db/conf/cscwd/cscwd2007.html#SunGML07