1. I. Juhász, Über ein Mächtigkeitsproblem für topologische Räume,Annales Univ. Sci. Budapest, Sectio Math.,8 (1965), pp. 75–82.
2. J. de Groot, Discrete subspaces of Hausdorff spaces,Bull. Acad. Sci. Pol.,13 (1966), pp. 537–544.
3. B. Pospišíl, On bicompact spaces,Publ. Fac. Sci. Univ. Masaryk,270 (1939).
4. B. Pospišíl,Časopis pro Pestov. Mat. a Fys.,37 (1937–38), pp. 89–96.
5. P. Erdős andA. Tarski, On families of mutually exclusive sets,Annals of Math.,44 (1943), pp. 315–329.