[1] BEČVÁŘ J., JAMBOR P.: On general concept of basic subgroups. Comment. Math. Univ. Carolinae 13 (1972), 745-761. MR 0315017

[2] FUCHS L.: Abelian groups. Budapest 1958. MR 0106942 | Zbl 0091.02704

[3] FUCHS L.: Infinite abelian groups I. Acad. Press 1970. MR 0255673

[4] KRÓL M.: Separable groups, I. Bull. Acad. Pol. des Sci. (5) 9 (1961), 337-344. MR 0142628

[5] MYŠKIN V. I.: Odnorodnye separabel'nye abelevy gruppy bez kručenija. Mat. sbornik 64 (1964), 3-9. MR 0165004