RAMAZANOVA, Kh.S. On the existence of focal and conjugate points of half-linear second-order differential equation on a given interval. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 77, n. 1, p. 72–78, 2015. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/14. Acesso em: 26 aug. 2025.