ALMALAHI, M. A.; PANCHAL, S. K. Existence and $\delta $-Approximate solution of implicit fractional pantograph equations in the frame of Hilfer-Katugampola operator. Journal of Fractional Calculus and Nonlinear Systems, [S. l.], v. 2, n. 1, p. 1–17, 2021. DOI: 10.48185/jfcns.v2i1.59. Disponível em: https://www.sabapub.com/index.php/jfcns/article/view/59. Acesso em: 29 mar. 2024.