GUO, Y. Solvability of boundary-value problems for nonlinear fractional differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 9, p. 1211–1219, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2949. Acesso em: 14 apr. 2025.