TY  - BOOK
AU  - Polkowski Lech
TI  - Rough sets: mathematical foundations
SN  - 3-7908-1447-4
U1  - 006.3 
PY  - 2002///
CY  - Heidelberg
PB  - Physica-Verlag
KW  - Fuzzy sets
KW  - Rough sets
ER  -