References
- J. Math. Anal. Appl. v.84 Fuzzy groups P.S.Das
- Math. Japon. v.25 Filter theory of BCK-algebras E.Y.Deeba
- Proc. Japan Academy v.42 On axiom systems of propositional calculi Y.Imai;K.Iseki
- Math. Seminar Notes(presently, Kobe J. Math.) v.3 On ideals in BCK-algebras K.Iseki
- Math. Japon. v.23 An introduction to the theory of BCK-algebras K.Iseki;S.Tanaka
- Math. Japonica Fuzzy BCK-filters Y.B.Jun;S.M.Hong;J.Meng
- Math. Japon. v.44 BCK-filters J.Meng
- BCK-algebras J.Meng;Y.B.Jun
- J. Math. Anal. Appl. v.35 Fuzzy groups A.Rosenfeld
- Math. Japon. v.36 Fuzzy BCK-algebras O.G.Xi
- Inform. Control v.8 Fuzzy sets L.A.Zadeh