MOHAMMED, A. A. . Solving Some Types of the Second and Third Order Spectral Linear Ordinary Differential Equations . JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences, [S. l.], v. 28, n. 1, p. 12–24, 2020. Disponível em: https://journalofbabylon.com/index.php/JUBPAS/article/view/2952. Acesso em: 18 aug. 2022.