1. L. V. Shabunin, “Decidability of the theories of finitely-related quasigroups inR-varieties of quasigroups” Sibirsk. Mat. Zh.,32, No. 3, 201–211 (1991).
2. L. V. Shabunin, “Decidability of the elementary theories of some finitely-related algebras,” Algebra i Logika,30, No. 4, 457–476 (1991).
3. A. I. Mal'tsev, “Axiomatizable classes of locally free algebras of certain types,” Sibirsk. Mat. Zh.3, No. 5, 729–743 (1962).
4. D. M. Smirnov, Varieties of Algebras [in Russian], Nauka, Novosibirsk (1992).
5. Yu. L. Ershov and E. A. Palyutin, Mathematical Logic [in Russian], Nauka, Moscow (1979).