1. Abstract and Concrete Categories;Adamek,1990
2. N. Blasco, Compactification and Convergence-Supercategories of FNS, Ph.D. Dissertation, University of Antwerp, Belgium, 1995.
3. Fuzzy topological spaces;Chang;J. Math. Anal. Appl.,1968
4. Convergence;Gähler;Fuzzy Sets and Systems,1995
5. U. Höhle, S.E. Rodabaugh (Eds.), Mathematics of Fuzzy Sets: Logic, Topology and Measure Theory, Kluwer Academic Publishers, Norwell, MA, 1999.