PRONSKA, N. Spectral properties of Sturm-Liouville equations with singular energy-dependent potentials. Methods of Functional Analysis and Topology, [S. l.], v. 19, n. 4, p. 327–345, 2013. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/557. Acesso em: 18 dec. 2025.