GOPAL, N. S.; JONNALAGADDA, J. M. Positive solutions of nabla fractional boundary value problem. CUBO, A Mathematical Journal, [S. l.], v. 24, n. 3, p. 467–484, 2022. DOI: 10.56754/0719-0646.2403.0467. Disponível em: https://cubo.ufro.cl/ojs/index.php/cubo/article/view/3210. Acesso em: 19 apr. 2024.