L. A. Zadeh, The concept of linguistic variable and its application in approximate reasoning, Information Science, vol.8, issue.9, 1975.

M. D. Glas, Representation of Lukasiewicz' many-valued algebras; the atomic case. Fuzzy Sets and Systems, 1987.

H. Akdag, M. D. Glas, and D. Pacholczyk, A qualitative theory of uncertainty, Fundamenta Informaticae, vol.17, issue.4, pp.333-362, 1992.

A. Darwiche and M. Ginsberg, A symbolic generalization of probability theory, proceedings of the American Association for Artificial Intelligence, 1992.

H. Seridi and H. Akdag, Approximate Reasoning for Processing Uncertainty, Journal of Advanced Computational Intelligence and Intelligent Informatics, vol.5, issue.2, pp.108-116, 2001.
DOI : 10.20965/jaciii.2001.p0110

H. Akdag, I. Truck, A. Borgi, and N. Mellouli, LINGUISTIC MODIFIERS IN A SYMBOLIC FRAMEWORK, International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems, vol.3, issue.supp01, pp.49-61, 2001.
DOI : 10.1037/0096-3445.105.3.254
URL : https://hal.archives-ouvertes.fr/hal-01184405

H. Seridi and H. Akdag, Approximate Reasoning for Processing Uncertainty, Journal of Advanced Computational Intelligence and Intelligent Informatics, vol.5, issue.2, pp.108-116, 2001.
DOI : 10.20965/jaciii.2001.p0110

J. Mendel and R. John, Type-2 fuzzy sets made simple, IEEE Transactions on Fuzzy Systems, vol.10, issue.2, pp.117-127, 2002.
DOI : 10.1109/91.995115

I. Truck and H. Akdag, Fuzzy Systems Engineering Theory and Practice, Series: Studies in Fuzziness and Soft Computing A Qualitative Approach for symbolic Data Manipulation under Uncertainty, pp.23-51, 2005.