1. Abstract and Concrete Categories;Adamek,1989
2. Regular convergence spaces;Biesterfeld;Indag. Math.,1966
3. Probabilistic convergence spaces and regularity;Brock;Int. J. Math. Math. Sci.,1997
4. E. Čech, Topological Spaces, Wiley, London, 1966.
5. On continuous extensions;Cook;Math. Ann.,1968