Fernando Bobillo Umberto Straccia Supporting Fuzzy Rough Sets in Fuzzy Description Logics. 676-687 2009 ECSQARU http://dx.doi.org/10.1007/978-3-642-02906-6_58 conf/ecsqaru/2009 db/conf/ecsqaru/ecsqaru2009.html#BobilloS09