D.B. DHAIGUDE; N.B. JADHAV; J.A. NANWARE. Method of upper lower solutions for nonlinear system of fractional differential equations and applications. Malaya Journal of Matematik, India, v. 6, n. 03, p. 467–472, 2018. DOI: 10.26637/MJM0603/0001. Disponível em: https://www.malayajournal.org/index.php/mjm/article/view/821. Acesso em: 16 jul. 2024.