[1] J. Adamek, H. Herrlich and G. Strecker, Abstract and concrete categories, Wiley Interscience,
1990.
[2] P. Corsini, Fuzzy sets of type 2 and hyperstructures, Proceedings of the 8th Int. Congress of
Algebraic Hyperstructures and Applications, 2002, Samothraki, Hadronic Press, 2003.
[3] P. Corsini and V. Leoreanu, Applications of hyperstruycture theory, Kluwer Academic Publishers,
Boston/ Dordrecht/ London, 2003.
[4] M. M. Ebrahimi, A. Karimi and M. Mahmoudi, Limits and colimits in universal hyperalgebra,
Algebras Groups and Geometries, 22 (2005), 169–182.
[5] G. Gr¨atzer, Universal algebra, Second Edition, Springer–Verlag, New York, Inc., 1979.
[6] V. Leoreanu Fotea, Direct limit and inverse limit of join spaces associated with fuzzy sets,
PU. M. A., 11 (2000).
[7] F. Marty, Sur une g´en´eralization de la notion de groupe, IV Congr`es des Math´ematiciens
Scandinaves, Stockholm, 1934.
[8] C. Pelea, On the direct limit of a direct system of complete multialgebras, Stud. Univ. Babes-
Bolyai, Math., 49(1) (2004), 63–68.
[9] G. Romeo, Limite diretto di semi–ipergruppi e ipergruppi di associativit`a, Riv. Mat. Univ.
Parma, 1982.
[10] D. Rutkovska and Y. Hayashi, Fuzzy inferenceneural networks with fuzzy parameters, Task
Quarterly, 1 (2003).
[11] L. A. Zadeh, The concept of a linguistic variable and its application to approximate
reasoning, Inform. Sci., I.8 (1975).