@article{DBLP:journals/tkde/ZhuW07,
author = {William Zhu and
Fei-Yue Wang},
title = {On Three Types of Covering-Based Rough Sets},
journal = {IEEE Trans. Knowl. Data Eng.},
volume = {19},
number = {8},
year = {2007},
pages = {1131-1144},
ee = {http://dx.doi.org/10.1109/TKDE.2007.1044},
bibsource = {DBLP, http://dblp.uni-trier.de}
}