Agarwala, Ravi P. P., and Bessem Samet. “An Existence Result for a Class of Nonlinear Integral Equations of Fractional Orders”. Nonlinear Analysis: Modelling and Control, vol. 21, no. 5, Sept. 2016, pp. 716-29, https://doi.org/10.15388/NA.2016.5.10.