Xueling Ma Jianming Zhan Bijan Davvaz Young Bae Jun Some kinds of (epsilon, epsilon or q)-interval-valued fuzzy ideals of BCI-algebras 3738-3754 2008 178 Inf. Sci. 19 http://dx.doi.org/10.1016/j.ins.2008.06.006 db/journals/isci/isci178.html#MaZDJ08