KONSTANTINOV, A. Yu. Spectral and scattering theory of some matrix operators related to the Schrödinger equations with potentials depending rationally on spectral parameter. Methods of Functional Analysis and Topology, [S. l.], v. 2, n. 3, p. 69–77, 1996. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/21. Acesso em: 19 dec. 2025.