ZAITSEV , D. I. On direct decompositions of infinite Abelian groups with operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 40, n. 3, p. 303–309, 1988. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9139. Acesso em: 7 dec. 2025.