[1] Hewitt E., K. A. Ross,: Abstract Harmonic Analysis I. Die Grundlehren der Mathematische Wissenschaften in Einzeldarstellungen (band 115), Springer, Berlin 1963.

[2] Juhász I.,: Cardinal functions in topology. MCT, No. 34. Mathematisch Centrum, Amsterdam, 1971. MR 0340021

[3] Priestly W. M.,: A sequentially closed countable dense subset of $I^I$. Proc. Amer. Math. Soc. 24 (1970), 270-277. MR 0249547

[4] Simon P.: Divergent sequences in compact Hausdorff spaces. Coll. Math. Soc. Janos Bolyai 23, Topology, Budapest (Hungary), 1978, pp. 1087-1094. MR 0588856