Li, Y., and L. Sun. “Infinite Many Positive Solutions for Nonlinear First-Order BVPs With Integral Boundary Conditions on Time Scales”. Topological Methods in Nonlinear Analysis, vol. 41, no. 2, Apr. 2013, pp. 305-21, https://apcz.umk.pl/TMNA/article/view/TMNA.2013.014.