ASLANOVA, N. M.; BAIRAMOGLY, M. Distribution of eigenvalues and trace formula for the Sturm–Liouville operator equation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 7, p. 867–877, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2920. Acesso em: 14 apr. 2025.