Abstract
We investigate the existence of at least one or two positive solu-tions of a system of two Riemann-Liouville fractional differential equations with delta-Laplacian operators and singular nonlinearities, supplemented with coupled nonlocal boundary conditions which contain Riemann-Stieltjes inte-grals and several fractional derivatives of different orders. We apply the Guo-Krasnosel'skii fixed point theorem in the proof of our main existence results.