Remili, Moussadek, and Mebrouk Rahmane. “Sufficient Conditions for the Boundedness and Square Integrability of Solutions of Fourth-Order Differential Equations”. Proyecciones (Antofagasta, On line) 35, no. 1 (March 23, 2017): 41-61. Accessed April 29, 2024. https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/1234.