1. Alperin, J. L. Groups with finitely many automorphisms. Pacific J. Math., 1962, 12(1), 1–5.
2. Belousov, V. D. Foundations of the Theory of Quasigroups and Loops. Nauka, Moscow, 1967 (in Russian).
3. Havel, V. and Sedlářová, M. Golden section quasigroups as special idempotent medial quasigroups. Acta Univ. Palack. Olomuc. Fac. Rerum Natur. Math., 1994, 33, 43–50.
4. Krylov, P. A., Mikhalev, A. V., and Tuganbaev, A. A. Endomorphism Rings of Abelian Groups. Kluwer Academic Publisher, Dordrecht–Boston–London, 2003.
5. Murdoch, D. C. Structure of Abelian quasi-groups. Trans. Amer. Math. Soc., 1941, 49, 392–409.
doi:10.1090/S0002-9947-1941-0003427-2
6. Puusemp, P. Idempotents of the endomorphism semigroups of groups. Acta Comment. Univ. Tartuensis, 1975, 366, 76–104 (in Russian).
7. Shcherbacov, V. A. On the structure of finite medial semigroups. Bul. Acad. Sti. Rep. Moldova, Matematica, 2005, 47(1), 11–18.
8. Tabarov, A. Kh. Homomorphisms and endomorphisms of linear and alinear quasigroups. Discrete Math. Appl., 2007, 17(3), 253–260.doi:10.1515/dma.2007.021