[AHS] J. Adámek H. Herrlich G. Strecker: 
Abstract and concrete categories. John Wiley & Sons Inc, New Yoгk, 1990. 
MR 1051419[AU] P. S. Alexandrov P. S. Urysohn: Mémoire sur les espaces topologiques compacts. Verh. Akad. Wetensch. Amsterdam 14 (1929).
[BE] N. G. de Bruijn P. Erdős: 
A colour problem for infinite graphs and a problem in the theory of relations. Nederl. Akad. Wetensch. Proc Sec. A 54 = Indag. Math. 13 (1951), 369-373. 
MR 0046630[CN] W. W. Comfort S. Negrepontis: 
The Theory of Ultrafilters. Springer-Verlag, Berlin-Heidelberg-New York, 1974. 
MR 0396267[vD] E. K. van Douwen: 
The integers and topology. Handbook of Set-Theoretic Topology, Chapter 3 (K. Kunen and J. E. Vaughan, eds.). pp. 111-167. 
MR 0776622 | 
Zbl 0561.54004[GJ] L. Gillman M. Jerison: 
Rings of Continuous Functions. Van Nostrand, New York, 1960. 
MR 0116199[He] H. Herrlich: 
Categorical topology 1971-1981. General Topology and its Relations to Modern Analysis and Algebra, Prague 1981. Heldermann, Berlin, 1982, pp. 279-383. 
MR 0698425[Hu] M. Hušek: 
S-categories. Comment. Math. Univ. Carolin. 5 (1964), 37-46. 
MR 0174027[KST] K. Kunen A. Szymański F. D. Tall: 
Baire irresolvable spaces and ideal theory. Ann. Math. Sil. 14 (1986), 98-107. 
MR 0861505