DANCHEV, P. V. Weakly clean and exchange UNI rings. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 71, n. 12, p. 1618–1625, 2019. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2288. Acesso em: 5 dec. 2025.