5Pawlak Z.Rough set[J].International Journal of Computer and Information Science, 1982( 11 ) :341-356.
6Pawlak Z.Rough set:Theoretical aspects of reasoning about data[M]. Boston:Kluwer Academic Publishers, 1991.
7Skowron A,Rauszer C.The discernibility matrices and functions in information systems[M].Boston:Kluwer Academic Publishers, 1992: 331-362.
8Kryszkiewicz M.Comparative study of alternative type of knowledge reduction in inconsistent systems[J].International Journal of Intelligent Systems, 2001,16(1) : 105-120.
9Kryszkiewicz M.Rough set approach to incomplete information systems[J].Information Sciences, 1998,112( 1 ) : 39-49.
10Wen-Xiu Zhang,Ju-Sheng Mi.Incomplete information system and its optimal selections[J].Computers and Mathematics with Applications, 2004,48 : 691-698.
