References
- S.S. Ahn, Y.U. Cho & C.H. Park: Vague quick ideals of BCK/BCI-algebras. Honam Math. J. 30 (2008), 65-74. https://doi.org/10.5831/HMJ.2008.30.1.065
- S.S. Ahn & J.M. Ko: On Vague filters in BE-algebras. Commun. Korean Math. Soc. 26 (2011), 417-425. https://doi.org/10.4134/CKMS.2011.26.3.417
- R. Biswas: Vague groups. Internat. J. Comput. Cognition 4 (2006), 20-23.
- W.L. Gau & D.J. Buehrer: Vague setsd. IEEE Transactions on Systems, Man and Cybernetics 23 (1993), 610-614. https://doi.org/10.1109/21.229476
- K. Iseki & S. Tanaka: An introduction to theory of BCK-algebras. Math. Jpn. 23 (1978), 1-26.
- K. Iseki: On BCI-algebras. Math. Seminar Notes 8 (1980), 125-130.
- Y.B. Jun & C.H. Park: Vague ideals of subtraction algebra. Int. Math. Forum. 2 (2007), 2919-2926. https://doi.org/10.12988/imf.2007.07266
- H.S. Kim & Y.H. Kim: On BE-algebras. Sci. Math. Jpn. 66 (2007), 113-116.
- K.L. Lee, K.S. So & K.S. Bang: Vague BCK/BCI-algebras. J. Korean Soc. Math. Educ. Ser. B: Pure Appl. Math. 15 (2008), 297-308.
- J. Meng & Y.B. Jun: BCK-algebras. Kyung Moon Sa, Co., Seoul (1994).
- C.H. Park: Vague deductive systems of subtraction algebras. J. Appl. Math. Informatics 26 (2008), 427-436.
- L.A. Zadeh: Fuzzy sets. Inform. Control 56 (2008), 338-353.