Upper and Lower Solution method for Positive solution of generalized Caputo fractional differential equations. Advances in the Theory of Nonlinear Analysis and its Application, [S. l.], v. 4, n. 4, p. 279–291, 2023. Disponível em: https://atnaea.org/index.php/journal/article/view/130.. Acesso em: 10 jun. 2026.