Multiple Positive Solutions to Singular Fractional Differential System with Riemann-Stieltjes Integral Boundary Condition. Communications in Mathematical Research, [S. l.], v. 35, n. 3, p. 208–218, 2019. DOI: 10.13447/j.1674-5647.2019.03.02. Disponível em: https://global-sci.com/index.php/cmr/article/view/9002. Acesso em: 5 dec. 2025.