On some generalization of normal operators on Hilbert space. Iraqi Journal of Science, [S. l.], v. 57, n. 2C, p. 178 6–179 4, 2023. Disponível em: https://www.ijs.uobaghdad.edu.iq/index.php/eijs/article/view/10044.. Acesso em: 5 jul. 2025.