1. Structure of Decision: the Cognitive Maps of Political Elites;Axelrod,1976
2. Fuzzy power sets and Fuzzy implication operators;Bandler;Fuzzy Sets and Systems,1980
3. Operations on fuzzy sets and fuzzy numbers related to triangular norms;Klement,1981
4. Comments on “Textured Sets. An Approach to Aggregation Problems with Multiple Concerns”;Yager;IEEE Transactions on Systems, Man, and Cybernetics,1981