1. M. Suzuki, Structure of a Group and Structure of a Lattice of Its Subgroups [Russian translation], IL, Moscow (1960).
2. M. I. Kargapolov and Yu. I. Merzlyakov, Foundations of Group Theory [in Russian], Nauka, Moscow (1972).
3. S. A. Anishchenko, "Representation of modular lattices by lattices of subgroups," Matem. Zap. Krasnoyarskogo Gos. Ped. In-ta, No. 1, 1?21 (1965).
4. L. E. Sadovskii, "Lattice isomorphisms of free groups and free products," Matem. Sb.,14, No. 1?2, 155?173 (1944).
5. B. I. Plotkin, "Problems of the theory of torsion-free groups," Ukr. Matem. Zh.,8, No. 3, 325?329 (1956).