[1] C. S. Hoo, K. P. Shum: On compact N-semigroups. Czechoslovak Math. J. 24 (99) (1974), 552-562. MR 0374321 | Zbl 0332.22003

[2] R. J. Koch: Remarks on primitive idempotents in compact semigroups with zero. Proc. Amer. Math. Soc. 5 (1954), 828-833. DOI 10.1090/S0002-9939-1954-0065569-X | MR 0065569 | Zbl 0056.02704

[3] R. J. Koch, A. D. Wallace: Maximal ideals in compact semigroups. Duke Math. J. 21 (1954), 681-685. DOI 10.1215/S0012-7094-54-02170-5 | MR 0063381 | Zbl 0057.01502

[4] N. H. McCoy: The theory of rings. Chelsea Publishing Company, New York (1973), MR 0393090 | Zbl 0273.16001

[5] K. Numakura: On bicompact semigroups with zero. Bull. Yamagata University (Natural. Science), 4 (1951), 405 -412. MR 0065568

[6] K. Numakura: On bicompact semigroups. Math. J. Okayama University, 1 (1952), 99-108. MR 0048467 | Zbl 0047.25502

[71 K. Numakura: Prime ideals and idempotents in compact semigroups. Duke Math. J. 24 (1957), 671-680. MR 0091426

[8] A. B. Paalman, de Miranda: Topological semigroups. Mathematical Centre Tracts, Amsterdam (1970). Zbl 0242.22003

[9] K. P. Shum: On compressed ideals in topological semigroups. Czechoslovak Math. J. 25 (100) (1975), 261-273. MR 0369602 | Zbl 0316.22004