[1] Clifford A. H., Preston G. B.: The algebraic theory of semigroups. Vol. I, Math. Surveys, No. 7, Amer. Math. Society, Providence, R. I., 1961. MR 0132791 | Zbl 0111.03403

[2] Dubreil P.: Algébre. Gauthier-Villars, Paris, second ed., 1954. MR 0064746 | Zbl 0057.25001

[3] Глускин Л. М.: Вполне простые полугруппы. Уч. зап. Харьковского пед. ин-та 18 (1956), 41-55. MR 0098399 | Zbl 0995.90522

[4] Ляпин Е. С.: Полугруппы. Гос. изд. физ-мат. лит., Mocквa, 1960. Zbl 1004.90500

[5] Preston G. B.: Congruences on completely 0-simple semigroups. Proc. London Math. Soc. (3) 11 (1961), 557-576. MR 0132792 | Zbl 0097.25203

[6] Stoll R. R.: Homomorphism of a semigroup onto a group. Amer. J. Math. 73 (1951), 475-481. MR 0041128

[7] Schwarz Š.: Subsemigroups of a simple semigroup. Czechoslovak Math. J. 13 (88) (1963). To appear. MR 0158014

[8] Schwarz Š.: Probabilities on non-commutative semigroups. Czechoslovak Math. J. 13 (88) (1963). To appear. MR 0160191 | Zbl 0137.35302

[9] Schwarz Š.: Convolution semigroup of measures on compact non-commutative semigroups. Czechoslovak Math. J. To appear.

[10] Schwarz Š.: Probability measures on non-commutative semigroups. Proceedings of the International symposion on topology, Prague 1961. Publ. House Czechoslovak Acad. Sci. Prague 1962. MR 0173721