[1] R. Belohlavek, Fuzzy relational systems: foundations and principles, Kluwer Academic/
Plenum Publishers, New York, 2002.
[2] R. Belohlavek and V. Vychodil, Fuzzy equational logic, Studies in Fuzziness and Soft Computing,
Springer 2005, 186 (2005).
[3] R. Belohlavek and V. Vychodil, Algebras with fuzzy equalities, Fuzzy Sets and Systems, 157
(2006), 161-201.
[4] A. Borumand Saeid, Interval-valued fuzzy B-algebras, Iranian Journal of Fuzzy Systems, 3(2)
(2006), 63{73.
[5] R. A. Borzooei and M. Bakhshi, Some properties of T-fuzzy generalized subgroups, Iranian
Journal of Fuzzy Systems, 6(4) (2009), 73{87.
[6] B. Budimirovic, V. Budimirovic, B. Seselja and A. Tepavcevic, Compatible fuzzy equalities
and fuzzy identities, preprint.
[7] B. Budimirovic, V. Budimirovic and A. Tepavcevic, Fuzzy "-subgroups, Information Sciences,
180 (2010), 4006-4014.
[8] S. Burris and H. P. Sankappanavar, A course in universal algebra, Springer-Verlag, N. Y.,
1981.
[9] A. B. Chakraborty and S. S. Khare, Fuzzy homomorphism and algebraic structures, Fuzzy
Sets and Systems, 59 (1993), 211{221.
[10] P. S. Das, Fuzzy groups and level subgroups, J. Math. Anal. Appl., 84 (1981), 264-269.
[11] M. Demirci, Vague groups, J. Math. Anal. Appl., 230 (1999), 142-156.
[12] M. Demirci, Foundations of fuzzy functions and vague algebra based on many-valued equiva-
lence relations part I: fuzzy functions and their applications, part II: vague algebraic notions,
part III: constructions of vague algebraic notions and vague arithmetic operations, Int. J.
General Systems, 32(3) (2003), 123-155, 157-175, 177-201.
[13] A. Di Nola and G. Gerla, Lattice valued algebras, Stochastica, 11 (1987), 137-150.
[14] L. Filep, Study of fuzzy algebras and relations from a general viewpoint, Acta Math. Acad.
Paedagog. Nyhazi, 14 (1998), 49{55.
[15] U. Hohle, Quotients with respect to similarity relations, Fuzzy Sets and Systems, 27 (1988),
31-44.
[16] T. Kuraoka and N. Y. Suzuki, Lattice of fuzzy subalgebras in universal algebra, Algebra
universalis, 47 (2002), 223{237.
[17] X. Luo and J. Fang, Fuzzifying Closure Systems And Closure Operators, Iranian Journal of
Fuzzy Systems, 8(1) (2011), 77{94.
[18] J. N. Malik, D.S. Mordeson and N. Kuroki, Fuzzy Semigroups, Springer, 2003.
[19] V. Murali, Fuzzy congruence relations, Fuzzy Sets and Systems, 41(1991), 359{369.
[20] A. Rosenfeld, Fuzzy groups, J. Math. Anal. Appl., 36 (1971), 512{517.
[21] B. Seselja, Characterization of fuzzy equivalence relations and of fuzzy congruence relations
on algebras, Review of Research Faculty of Science { University of Novi Sad, 11 (1981), 153{
160.
[22] B. Seselja, Homomorphisms of poset-valued algebras, Fuzzy Sets and Systems, 121 (2001),
333{340.
[23] B. Seselja and A. Tepavcevic, Fuzzy Boolean algebras, Automated Reasoning, IFIP Transactions
A-19, (1992), 83{88.
[24] B. Seselja and A. Tepavcevic, Partially ordered and relational valued algebras and congru-
ences, Review of Research, Faculty of Science, Mathematical Series, 23 (1993), 273{287.
[25] B. Seselja and A. Tepavcevic, On generalizations of fuzzy algebras and congruences, Fuzzy
Sets and Systems, 65 (1994), 85{94.
[26] B. Seselja and A. Tepavcevic, Fuzzy groups and collections of subgroups, Fuzzy Sets and
Systems, 83 (1996), 85{91.
[27] B. Seselja and A. Tepavcevic, A note on fuzzy groups, YUJOR, 7(1) (1997), 49{54.
[28] B. Seselja and A. Tepavcevic, Fuzzy identities, Proc. of the 2009 IEEE International Conference
on Fuzzy Systems, 1660{1664.
[29] A. P. Sostak, On a fuzzy topological structure, Frolk, Z., Soucek, V. and Vinarek, J. eds.:
Proceedings of the 13th Winter School on Abstract Analysis. Section of Topology, Palermo,
(1985), 89{103.
[30] R. T. Yeh and S. Y. Bang, Fuzzy relations, fuzzy graphs, and their application to clyster-
ing analysis, L. A. Zadeh, K. S. Fu, K. Tanaka, M. Shimura, eds.: Fuzzy Sets and Their
Applications to Cognitive and Decision Processes, Academic Press, Inc., (1975), 125{149.