Guo, Limin, and Lishan Liu. “Maximal and Minimal Iterative Positive Solutions for Singular Infinite-Point P-Laplacian Fractional Differential Equations”. Nonlinear Analysis: Modelling and Control 23, no. 6 (June 27, 2019): 851–865. Accessed July 18, 2024. https://www.journals.vu.lt/nonlinear-analysis/article/view/13147.