SAMOILENKO, V. G. Kato inequality for operators with infinitely many separated variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 5, p. 718–720, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4658. Acesso em: 6 dec. 2025.