BendriciN., BoutiaraA., and Boumedien-ZidaniM. “Existence Theory for $\psi$-Caputo Fractional Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 76, no. 9, Sept. 2024, pp. 1291 -03, doi:10.3842/umzh.v76i9.7669.