中国科学院数学与系统科学研究院期刊网
The Lower and Upper Approximations of Language Based on String Indiscernibility Relation-The application of rough set
Tian Yun ZHI;Duo Qian MIAO
Systems Engineering - Theory & Practice . 2002, (1): 79 -82 .  DOI: 10.12011/1000-6788(2002)1-79