HUMENCHUK, H. I. On the sum of narrow and finite-rank orthogonally additive operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 67, n. 12, p. 1620–1625, 2015. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2095. Acesso em: 5 dec. 2025.