1. Abstract and Concrete Categories;Adámek,1990
2. Lattice Theory;Birkhoff,1973
3. Fuzzy topological spaces;Chang;J. Math. Anal. Appl.,1968
4. Compactness in fuzzy topological spaces;Gantner;J. Math. Anal. Appl.,1978
5. L-fuzzy sets;Goguen;J. Math. Anal. Appl.,1967