ZHURAVLEV, V. F. Solvability criterion and representation of solutions of $n$-normal and $d$-normal linear operator equations in a Banach space. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 2, p. 167–182, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2853. Acesso em: 5 dec. 2025.