JLELI, Mohamed; SAMET, Bessem. Existence of positive solutions to an arbitrary order fractional differential equation via a mixed monotone operator method. Nonlinear Analysis: Modelling and Control, [S. l.], v. 20, n. 3, p. 367–376, 2015. DOI: 10.15388/NA.2015.3.4. Disponível em: https://www.zurnalai.vu.lt/nonlinear-analysis/article/view/13520. Acesso em: 15 jun. 2025.