Qin, Haiyong. “Existence of Positive Solutions for Second-Order Nonlinear Impulsive Singular Questions With Integral Boundary Conditions in Banach Spaces”. International Journal Of Mathematics And Computer Research 6, no. 12 (December 18, 2018): 1943-1947. Accessed March 28, 2024. http://ijmcr.in/index.php/ijmcr/article/view/243.