GORYUNOV, A. S. Convergence and Approximation of the Sturm–Liouville Operators with Potentials-Distributions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 67, n. 5, p. 602–610, 2015. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2008. Acesso em: 5 dec. 2025.