Qiu, Xiaowei; Xu, Jiafa; O’Regan, Donal; Cui, Yujun (Hindawi Limited, 2018-01-01)
We study the existence of positive solutions for the system of nonlinear semipositone boundary value problems with RiemannLiouville fractional derivatives D(0+)(alpha)D(0+)(alpha)u = f(1)(t,u,u',v,v'), 0 < t < ...