PETRENKO, B. V. On direct decompositions in modules over group rings. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 2, p. 255–261, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5002. Acesso em: 11 apr. 2025.