Yong Liu Guoyin Wang Lin Feng A General Model for Transforming Vague Sets into Fuzzy Sets. 133-144 2008 2 Transactions on Computational Science http://dx.doi.org/10.1007/978-3-540-87563-5_8 journals/tcos/2008-2 db/journals/tcos/tcos2.html#LiuWF08