1. 1. P. Alexandroff and H. Hopf, Topologie I, Berlin, 1935.
2. Une généralisation des espaces compacts;Dieudonné, Jean;J. Math. Pures Appl. (9),1944
3. 3. C. Kuratowski, Topologie I, Warsaw 1933.
4. On the topological product of paracompact spaces;Sorgenfrey, R. H.;Bull. Amer. Math. Soc.,1947
5. Annals of Mathematics Studies, No. 2;Tukey, John W.,1940