[1] N. Ajmal and K. V. Thomas, A complete study of the lattice of fuzzy congruence and fuzzy
normal subgroups, Information Sciences, 82 (1995), 197-218.
[2] R. Ameri and M. M. Zahedi, Hyperalgebraic systems, Italian J. Pure Appl. Math., 6 (1999),
21-32.
[3] J. M. Anthony and H. Sherwood, Fuzzy groups redefined, J. Math. Anal. Appl., 69 (1979),
124-130
[4] S. K. Bhakat, (2, 2 _q)-fuzzy normal, quasinormal and maximal subgroups, Fuzzy Sets and
Systems, 112 (2000), 299-312.
[5] S. K. Bhakat, (2 _q)-level subsets, Fuzzy Sets and Systems, 103 (1999), 529-533.
[6] S. K. Bhakat and P. Das, On the definition of a fuzzy subgroup, Fuzzy Sets and Systems, 51
(1992), 235-241.
[7] S. K. Bhakat and P. Das, (2, 2 _q)-fuzzy subgroup, Fuzzy Sets and Systems, 80 (1996),
359-368.
[8] S. K. Bhakat and P. Das, Fuzzy subrings and ideals redefined, Fuzzy Sets and Systems, 81
(1996), 383-393.
[9] P. Bhattacharya, Fuzzy subgroups: some characterizations. II, Information Sciences, 38
(1986), 293-297.
[10] P. Bonansinga and P. Corsini, Sugli omomorfismi di semi-ipergruppi e di ipergruppi, B.U.M.I.,
1-B, 1982.
[11] S. D. Comer, Polygroups derived from cogroups, J. Algebra, 89 (1984), 397-405.
[12] S. D. Comer, Combinatorial aspects of relations, Algebra Universalis, 18 (1984), 77-94.
[13] S. D. Comer, Extension of polygroups by polygroups and their representations using colour
schemes, Lecture notes in Meth., No 1004, Universal Algebra and Lattice Theory, (1982),
91-103.
[14] S. D. Comer, A new fundation for theory of relations, Notre Dame J. Formal Logic, 24
(1983), 81-87.
[15] S. D. Comer, Hyperstructures associated with character algebra and color schemes, New
Frontiers in Hyperstructures, Hadronic Press, (1996), 49-66.
[16] P. Corsini, Prolegomena of hypergroup theory, Second Edition, Aviani Editor, 1993.
[17] P. Corsini, A new connection between hypergroups and fuzzy sets, Southeast Asian Bull.
Math., 27 (2)(2003), 221-229.
[18] P. Corsini, Join spaces, power sets, fuzzy sets, Proceedings of the fifth Int. Congress on Algebraic
Hyperstructures, Jasi, Romania, July 4-10, 1993, Hadronic Press, Inc., Palm Harbor,
1994.
[19] P. Corsini and V. Leoreanu, Applications of hyperstructures theory, Advanced in Mathematics,
Kluwer Academic Publishers, 2003.
[20] P. Corsini and V. Leoreanu, Fuzzy sets and join spaces associated with rough sets, Rend.
Circ. Mat., Palarmo 51 (2002), 527-536.
[21] P. Corsini and I. Tofan, On fuzzy hypergroups, Pure Math. Appl., 8 (1997), 29-37.
[22] P. S. Das, Fuzzy groups and level subgroups, J. Math. Anal. Appl., 85 (1981), 264-269.
[23] B. Davvaz, Fuzzy and anti fuzzy subhypergroups, Proc. International Conference on Intelligent
and Cognitive Systems, (1996), 140-144.
[24] B. Davvaz, Fuzzy Hv-groups, Fuzzy Sets and Systems, 101 (1999), 191-195.
[25] B. Davvaz, Fuzzy Hv-submodules, Fuzzy Sets and Systems, 117 (2001), 477-484.
[26] B. Davvaz and N. S. Poursalavati,On polygroup hyperrings and representations of polygroups,
J. Korean Math. Soc., 36 (6)(1999), 1021-1031.
[27] B. Davvaz, On polygroups and weak polygroups, Southeast Asian Bull. Math., 25 (2001),
87-95.
[28] B. Davvaz, Elementary topics on weak polygroups, Bull. Korean Math. Soc., 40 (1) (2003),
1-8.
[29] B. Davvaz, Fuzzy weak polygroups, Proc. 8th International Congress on Algebraic Hyperstructures
and Applications, 1-9 Sep., 2002, Samothraki, Greece, Spanidis Press, (2003),
127-135.
[30] B. Davvaz, Polygroups with hyperoperators, J. Fuzzy Math., 9 (4) (2001), 815-823.
[31] B. Davvaz, TL-subpolygroups of a polygroup, Pure Math. Appl., 12 (2) (2001), 137-145.
[32] B. Davvaz, On polygroups and permutation polygroups, Math. Balkanica (N.S.) 14 (1-2)
(2000), 41-58.
[33] A. Hasankhani and M. M. Zahedi, F-polygroups and fuzzy sub-F-polygroups, J. Fuzzy Math.
6 (1) (1998), 97-110.
[34] S. Ioulidis, Polygroups et certains de leurs properietes, Bull. Greek Math. Soc., 22 (1981),
95-104.
[35] Ath. Kehagias, L-fuzzy join and meet hyperoperations and the associated L-fuzzy hyperalgebras,
Rend. Circ. Mat., Palermo, 51 (2002), 503-526.
[36] Ath. Kehagias, An example of L-fuzzy join space, Rend. Circ. Mat., Palermo, 52 (2003),
322-350.
[37] Leoreanu, Direct limit and inverse limit of join spaces associated with fuzzy sets, Pure Math.
Appl., 11 (2002), 509-512.
[38] F. Marty, Sur une generalization de la notion de group, 8th Congress Math. Scandenaves,
Stockholm, (1934), 45-49.
[39] J. Mittas, Hypergroupes canoniques, Math. Balkanica, Beograd, 2 (1972), 165-179.
[40] W. Prenowitz, Projective geometries as multigroups, Amer. J. Math., 65 (1943), 235-256.
[41] A. Rosenfeld, Fuzzy groups, J. Math. Anal. Appl., 35 (1971), 512-517.
[42] R. Roth, Character and conjugacy class hypergroups of a finite group, Annali di Matematica
Pura ed Appl., 105 (1975), 295-311.
[43] I. Tofan and A. Volf, On some connections betyween hyperstructures and fuzzy sets, International
Algebra Conference (Ia¸si, 1998) Ital. J. Pure Appl. Math., 7 (2000), 63-68.
[44] T. Vougiouklis, Hyperstructures and their representations, Hadronic Press, Inc, 115, Palm
Harber, USA 1994.
[45] M. S. Ying, On standard models of fuzzy modal logics, Fuzzy Sets and Systems, 26 (1988)
357-363.
[46] X. Yuan, C. Zhang and Y. Ren, Generalized fuzzy groups and many-valued implications,
Fuzzy Sets and Systems, 138 (2003), 205-211.
[47] L. A. Zadeh, Fuzzy sets, Inform. Control, 8 (1965), 338-353.
[48] M. M. Zahedi, M. Bolurian and A. Hasankhani, On polygroups and fuzzy subpolygroups, J.
Fuzzy Math., 3 (1995), 1-15.
[49] M. M. Zahedi and A. Hasankhani, F-polygroups I, J. Fuzzy Math., 4 (3) (1996), 533-548.
[50] M. M. Zahedi and A. Hasankhani, F-polygroups II, Information Sciences, 89 (3-4)(1996),
225-243.
[51] M. M. Zahedi, H. Kouchi and H. Moradi, (Anti)-fuzzy (normal) sub-F-polygroups and fuzzy
-coset, J. Discrete Math. Sci. Cryptography, 5 (1) (2002), 85-104.