1. Bustince, H., Burillo, P.: Mathematical analysis of interval-valued fuzzy relations: application to approximate reasoning. Fuzzy Sets Syst. 113, 205–219 (2000)
2. Chaneau, J.L., Gunaratne, M., Altschaeffl, A.G.: An application of type-2 sets to decision making in engineering. In: Bezdek, J. (ed.) Analysis of Fuzzy Information, vol. II: Artificial Intelligence and Decision Systems. CRC Press, Boca Raton, FL (1987)
3. Bounhas, M., Mellouli, K., Prade, H., Serrurier, M.: From Bayesian classifiers to possibilistic classifiers for numerical data. In: Deshpande, A., Hunter, A. (eds.) SUM 2010, LNAI 6379, pp. 112–125, Springer, Heidelberg (2010)
4. Dempster, A.P.: Upper and lower probabilities induced by a multivalued mapping. Ann. Math. Stat. 38(2), 325–339 (1967)
5. Operations in a fuzzy-valued logic. Inform. Control 43, 224–240 (1979)