LINCHUK, Yu. S. Cyclical elements of operators which are left-inverses to multiplication by an independent variable. Methods of Functional Analysis and Topology, [S. l.], v. 12, n. 4, p. 384–388, 2006. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/330. Acesso em: 16 dec. 2025.