Shawagfeh, N. T., & Glasser, M. L. (2011). Uniform asymptotic solutions of second order linear differential equations with double pole and turning point. Rev. Téc. Fac. Ing. Univ. Zulia, 13(1). Recuperado a partir de https://mail.produccioncientificaluz.org/index.php/tecnica/article/view/5354