Benchohra, M., G. M. N‘Guérékata, and D. Seba. “Measure of Noncompactness and Nondensely Defined Semilinear Functional Differential Equations With Fractional Order”. CUBO, A Mathematical Journal, vol. 12, no. 3, Oct. 2010, pp. 35–48, doi:10.4067/S0719-06462010000300003.