1. Fuzzy sets;Zadeh;Inf. Control,1965
2. Aggregation operators and fuzzy systems modeling;Yager;Fuzzy Set Syst.,1994
3. Intuitionistic fuzzy sets;Atanassov;Fuzzy Set Syst.,1986
4. Pythagorean fuzzy subsets;Yager,2013
5. Pythagorean membership grades, complex numbers, and decision making;Yager;Int. J. Intell. Syst.,2013