1. A definition of nonprobabilistic entropy in the setting of fuzzy set theory;DeLuca;Information and Control,1972
2. On a generalization of quantifiers;Mostowski;Fundamenta Mathematicae,1957
3. Many-ValuedLogic;Rescher,1969
4. Introduction to Logic;Suppes,1957
5. A note on probabilities of fuzzy events;Yager;Information Science,1979