Fourth-order four point Sturn-Liouville boundary value problem with nonhomogeneous conditions. Global Journal of Science Frontier Research, [S. l.], v. 12, n. F1, p. 109–115, 2012. Disponível em: https://www.journalofscience.org/index.php/GJSFR/article/view/102012. Acesso em: 6 feb. 2026.