1. Local and fuzzy logics;Bellman,1976
2. Topological Spaces, Including a Treatment of Multi-valued Mappings;Berge,1963
3. Upper and lower probabilities induced by multi-valued mappings;Dempster;Ann. Math. Statist.,1967
4. Equations de relations floues;Sanchez;Thèse d'Etat de Biologie Humaine,1974