SINAISKY , E. S. Approximation method in one boundary value problem for linear differential equation with polynomial coefficients. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 40, n. 2, p. 248–253, 1988. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9127. Acesso em: 5 dec. 2025.