[1] Arhangel'skii A.V.: A general concept of splittability of a topological space (in Russian). in: Proceedings of the Fifth Tyraspol Symposium on General Topology and its Applications, Kishinev, Shtiintsa, 1985, 8-10.
[2] Arhangel'skii A.V., Shakhmatov D.B.: Splittable spaces and questions of functions approximations (in Russian). in: Proceedings of the Fifth Tyraspol Symposium on General Topology and its Applications, Kishinev, Shtiintsa, 1985, 10-11.
[3] Arhangel'skii A.V., Shakhmatov D.B.: 
On pointwise approximation of arbitrary functions by countable families of continuous functions (in Russian). Trudy Seminara I.G. Petrovskogo 13 (1988), 206-227. 
MR 0961436[4] Tkachuk V.V.: 
Approximation of $\bold R^X$ with countable subsets of $C_p(X)$ and calibers of the space $C_p(X)$. Comment. Math. Univ. Carolinae 27 (1986), 267-276. 
MR 0857546[5] Bregman Yu.H., Šapirovskii B.E., Šostak A.P.: 
On partition of topological spaces. Časopis pro pěstování mat. 109 (1984), 27-53. 
MR 0741207[6] Mazurkiewicz S.: Sur les problèmes $\kappa $ et $\lambda $ de Urysohn. Fund. Math. 10 (1927), 311-319.
[7] Tkachuk V.: 
Remainders over discrete spaces - some applications (in Russian). Vestnik MGU, Mat., Mech., no. 4, 1990, 18-21. 
MR 1086601[8] Malyhin V.I.: 
$\beta N$ is prime. Bull. Acad. Polon. Sci., Ser. Mat. 27 (1979), 295-297. 
MR 0552052 | 
Zbl 0433.54015[10] Skljarenko E.G.: 
A theorem on maps, lowering dimension (in Russian). Bull. Acad. Polon. Sci., Ser. Mat. 10 (1962), 429-432. 
MR 0149445