1. Alsina, C., Trillas, E., & Valverde, L. (1980). On non-distributive logical connectives for fuzzy sets theory. Busefal, 3, 18–29.
2. Alsina, C., Trillas, E., & Valverde, L. (1983). On some logical connectives for fuzzy sets theory. Journal of Mathematical Analysis and Applications, 93, 15–26.
3. Ardeshir, M., & Ruitenburg, W. (1998). Basic propositional calculus I. Mathematical Logic Quarterly, 44, 317–343.
4. Baaz, M. (1996). Infinite-valued Gödel logics with 0–1 projections and relativizations. In P. Hájek (Ed.), Gödel’96 (pp. 23–33). Lecture Notes in Logic New York: Springer.
5. Bandler, W., & Kohout, L. (1980). Fuzzy power sets and fuzzy implication operators. Fuzzy Sets and Systems, 4, 183–190.