REFERENCES RELATED TO DEFINITIONS OF OPERATORS:

Gougen, J.A. (1969) The logic of inexact concepts. Synthese, Vol. 19,
    pp 325-373.
Osherson, D.N., & Smith, E.E. (1981) On the adequacy of prototype theory
    as a theory of concepts.  Cognition. Vol. 9, pp. 35-38.
Osherson, D.N., & Smith, E.E. (1982) Gradedness and conceptual
    combination. Cognition, Vol. 12, pp. 299-318.
Roth, E.M., & Mervis, C.B. (1983) Fuzzy set theory and class inclusion
    relations in semantic categories. Journal of Verbal Learning and
    Verbal Behavior, Vol. 22, pp. 509-525.
Zadeh, L.A. (1982) A note on prototype theory and fuzzy sets.
    Cognition, Vol. 12, pp. 291-297.


BASIC REFERENCE ON PROTOTYPE THEORY IN COGNITIVE PSYCHOLOGY:

Mervis, C.B., & Rosch, E.  (1981) Categorization of natural objects.
     Annual Review of Psychology, Vol. 32, pp. 89-115.


SELECTED REFERENCES ON FUZZY SET THEORY GENERALLY & AI APPLICATIONS:
Jain, R. Fuzzyism and real world problems.  In P.P. Wang & S.K. Chang
     (Eds.), Fuzzy Sets, New York: Plenum Press.
Zadeh, L.A. (1965)  Fuzzy sets.  Information and Control, Vol. 8,
     pp. 338-353.
Zadeh, L.A. (1978) PRUF - A meaning representation language
     for natural languages.  International Journal of Man-Machine Studies,
     Vol. 10, pp. 395-460.
Zadeh, L.A. (1983) The role of fuzzy logic in the
     management of uncertainty in expert systems.  Memorandum No. UCB/ERL
     M83/41, University of California, Berkeley.