GOMILKO, A. M.; PIVOVARCHIK, V. N. Asymptotics of Solutions of the Sturm–Liouville Equation with Respect to a Parameter. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 53, n. 6, p. 742–757, 2001. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4297. Acesso em: 27 apr. 2025.