1. A. Robinson, Introduction to the Theory of Models and Metamathematical Algebra [Russian translation], Moscow (1967).
2. M. I. Kargapolov, “The elementary theory of Abelian groups,” Algebra i Logika,1, No. 6, 26–36 (1963).
3. Yu. L. Ershov, I. A. Lavrov, A. D. Taimanov, and M. A. Taitslin, “Elementary theory,” Ukrainsk. Matem. Zh.,20, No. 4 (124), 37–108 (1965).
4. A. G. Kurosh, The Theory of Groups [in Russian], Moscow (1967).
5. A. I. Kokorin and N. G. Khisamiev, “The elementary classification of structurally ordered Abelian groups with a finite number of threads,” Algebra i Logika,5, No. 1, 41–50 (1966).