SLYUSARCHUK, V. Yu. Generalization of the Kneser theorem on zeros of solutions of the equation $y" + p (t) y = 0$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 59, n. 4, p. 571–576, 2007. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3332. Acesso em: 5 dec. 2025.