SAKHNOVICH, L. A. Factorization of operators. Theory and applications. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 3, p. 293–304, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5762. Acesso em: 5 dec. 2025.