KOSHMANENKO, V. D.; OTA, S. On characteristic properties of singular operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 48, n. 11, p. 1484–1493, 1996. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5202. Acesso em: 14 apr. 2025.