1. Fuzzy set;Zadeh;Information and Control,1965
2. Intuitionistic fuzzy sets;Atanassov;Fuzzy Sets Syst,1986
3. Vague sets;Gau;IEEE Transactions on Systems, Man and Cybernetics,1993
4. Rough sets;Pawlak;International Journal of Information and Computer Sciences,1982
5. Neutrosophic set - A generalisation of the intuitionistic fuzzy sets;Smarandache;International Journal of Pure and Applied Mathematics,2005