[1] R. G. Bilyeu, A. Lau: Representations into the hyperspace of a compact group. Semigroup Forum, Vol. 13 (1977), 267-270. DOI 10.1007/BF02194945 | MR 0435282 | Zbl 0363.20053

[2] R. D. Byrd J. T. Lloyd F. D. Pedersen J. W. Stepp: Automorphisms of semigroups of complexes of Abelian groups. Bull. Amer. Math. Soc, Vol. 83 #2 (1977), 260-261. DOI 10.1090/S0002-9904-1977-14293-6 | MR 0424971

[31 H. B. Mann: Addition theorems: the addition theorems of group theory and number theory. Interscience Pub. (1965). MR 0424744

[4] L. Redei: The theory of finitely generated commutative semigroups. Pergamon Press (1965). DOI 10.1007/BF02194887 | MR 0188322 | Zbl 0133.27904

[5] V. Trnková: On a representation of commutative semigroups. Semigroup Forum, Vol. 10 #3 (1975), 203-214. MR 0374312

[6] M. Yamada: Construction of finite commutative $z$-semigroups. Proc. Japan Acad. Vol. 40 #2(1964), 94-98. MR 0163975 | Zbl 0121.26903

[7] M. Yamada: Construction of finite commutative semigroups. Bull. of Shimane Univ., No. 15 (1965), 1-11. MR 0393308