ZHANG, Xinguang; KONG, Dezhou; TIAN, Hui; WU, Yonghong; WIWATANAPATAPHEE, Benchawan. An upper-lower solution method for the eigenvalue problem of Hadamard-type singular fractional differential equation. Nonlinear Analysis: Modelling and Control, [S. l.], v. 27, n. 4, p. 789–802, 2022. DOI: 10.15388/namc.2022.27.27491. Disponível em: https://www.zurnalai.vu.lt/nonlinear-analysis/article/view/27491. Acesso em: 3 may. 2025.