Existence of extremal solutions of nonlinear discontinuous integral equations of Volterra type is proved. This result is extended herein to functional Volterra integral equations (FVIEs) and to a system of discontinuous VIEs as well.
"Existence Theorem for Integral and Functional Integral Equations with Discontinuous Kernels." Abstr. Appl. Anal. 2012 1 - 14, 2012. https://doi.org/10.1155/2012/232314