LINCHUK, Yu. S. On the equivalence of some perturbations of the operator of multiplication by the independent variable. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 68, n. 11, p. 1579–1584, 2016. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1944. Acesso em: 6 dec. 2025.