1. Fuchs, L.: Infinite Abelian groups, vol. 1. Mir, Moscow (1974) (in Russian)
2. Reid, C.D.: Finiteness properties of profinite groups. A thesis submitted by the University of London for the degree of Doctor of Philosophy, Queen Mary, University of London, 2010, February 10, LNCS Homepage.
http://www.maths.qmul.ac.uk/
3. Ershov, Yu.L: Profinite groups. Algebra Logic 19(5), 552–565 (1980)
4. Artamonov, V.A., Salii, V.N., Skornyakov, L.A., Shevrin, L.N., Shul’geifer, E.G.: General Algebra, vol. 2, p. 188. Science. Main Edition of the Physical and Mathematical Literature, Moscow (1991) (in Russian)
5. Cohn, P.M.: Universal algebra. Harper & Row Publishers, New York-London, N.Y. (1965)