KOVALYOV, I. Darboux transformation of generalized Jacobi matrices. Methods of Functional Analysis and Topology, [S. l.], v. 20, n. 4, p. 301–320, 2014. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/588. Acesso em: 16 dec. 2025.