Youcef, Z., K. Bachouche, and T. Moussaoui. “Existence of Nonnegative Solution for a Boundary Value Problem via Upper and Lower Method on the Half-Line”. Proyecciones (Antofagasta, On Line), vol. 43, no. 3, May 2024, pp. 665-82, doi:10.22199/issn.0717-6279-5202.