KARATAEVA, T. V. On the existence of a mixed sum of additive systems. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 6, p. 699–707, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5697. Acesso em: 5 dec. 2025.