W.-N. Liu, Jingtao Yao, Yiyu Yao. Rough Approximations under Level Fuzzy Sets. In Shusaku Tsumoto, Roman Slowinski, Henryk Jan Komorowski, Jerzy W. Grzymala-Busse, editors, Rough Sets and Current Trends in Computing, 4th International Conference, RSCTC 2004, Uppsala, Sweden, June 1-5, 2004, Proceedings. Volume 3066 of Lecture Notes in Computer Science, pages 78-83, Springer, 2004. [doi]
Abstract is missing.