On the Coupled System of Fractional Pantograph Differential Equations with psi-Caputo Fractional Derivatives. Nonlinear Studies, [S. l.], v. 31, n. 4, p. 1321–1334, 2024. Disponível em: https://www.nonlinearstudies.com/index.php/nonlinear/article/view/3215. Acesso em: 1 mar. 2026.