[1] ČECH E.: 
Topological Spaces. 2nd ed. Praha, Academia 1966. 
MR 0211373 
[2] HEDRLÍN Z.: 
An Application of Ramsay's Theorem to the Topological Products. Bull. Acad. Polon. Sol., XIV (1966), 1, 25-26.. 
MR 0203667 
[3] JUHÁSZ  I.: 
Cardinal functions in Topology. Mathematical Centre Tracts 34, Amsterdam, 1971. 
MR 0340021 
[4] KUREPA D.: 
The cartesian multiplication and the cellularity number. Publ. Inst. Math. (Beograd), 2 (1962), 121-139. 
MR 0177894 
[5] RUDIN M. E.: 
Souslin's conjecture. Amer. Math. Monthly, Vol. 76, No 10 (1969), 1113-1119. 
MR 0270322 | 
Zbl 0187.27302