1. Zadeh, L.A.: Fuzzy sets. Inf. Control 8, 338–353 (1965)
2. Dombi, J.: A general class of fuzzy operators, the de morgan class of fuzzy operators and fuzziness measures induced by fuzzy operators. Fuzzy Sets Syst. 8, 149–163 (1982). https://doi.org/10.1016/0165-0114(82)90005-7
3. Dombi, J.: Membership function as an evaluation. Fuzzy Sets Syst. 35, 1–22 (1990)
4. Bilgiç, T., Türkşen, I.B.: Measurement of membership functions theoretical and empirical work Fundamentals of fuzzy sets. Springer, Berlin (2000)
5. Medasani, S., Kim, J., Krishnapuram, R.: An overview of membership function generation techniques for pattern recognition. Int. J. Approx. Reason. 19, 391–417 (1998)