1. Kurosh, A.G.: Lectures on general algebra, Chelsea, 1963 (translated from the Russian)
2. Balci, D.: Zur Theorie der topologischen n-Gruppen, Minerva, Munich, 1981
3. Rusakov, S.A.: ‘The subgroup structure of Dedekind n-ary groups’, in Finite groups (Proc. Gomel. Sem.), Minsk, 1978, pp. 81–104 (in Russian)
4. Rusakov, S.A.: ‘On the theory of nilpotent n-ary groups’, in Finite groups (Proc. Gomel. Sem.), Minsk, 1978, pp. 104–130 (in Russian)
5. Court, N.A.: College geometry, Barnes & Noble, 1952, p. 160