Yalin Zheng Guang Yang 0002 Changshui Zhang Jing Zheng Yunpeng Xu Equivalence Knowledge Mass and Approximate Reasoning in -Logic (I). 391-400 2008 ICIC (2) http://dx.doi.org/10.1007/978-3-540-85984-0_48 conf/icic/2008-2 db/conf/icic/icic2008-2.html#ZhengYZZX08