[1] Clifford A. H., Preston G. B.: The algebraic theory of semigroups. I, Providence 1961. Zbl 0111.03403

[2] Гpмoвa P.: Oбoбщeнныe uдeaлы в noлyгpynnax. Mat.-fyz. časop. 13 (196З), 41-54.

[З] Kypoш A. Г.: Лeкцuu пo oбщeй aлгeбpe. Mocквa 1962.

[4] Ляпин E. C.: Пoлyгpynnы. Mocквa 1960.

[5] Швapц Ш.: O noлyгpynnax uмeющux ядpo. Чexocл. мaтeм. ж. 1 (76) (1951), 259-300.

[6] Schwaгz Š.: Subsemigroups of simple semigroups. Czechosl. Math. J. 13 (88) (1963), 226-239. MR 0158014

[7] Schwarz Š.: Homomorphisms of a completely simple semigroup onto a group. Mat.-fyz. časop. 12 (1962), 293-300. MR 0158942 | Zbl 0232.20131

[8] Schwarz Š.: Probabilities on non-commutative semigroups. Чехосл. матем. ж.. 13 (88) (1963), 372-426. MR 0160191 | Zbl 0137.35302

[9] Wallace A. D.: Relative ideals in semigroups I. Colloq. math. 9 (1962), 55-61. MR 0137102 | Zbl 0100.26002

[10] Wallace A. D.: Relative ideals in semigroups II. Acta math. Acad, scient. Hung. 14 (1963), 137-148. MR 0158017 | Zbl 0122.26802