D. M. Al-Rahal, Tran., “Classic Spline Functions for Approximate Solution of System of Non-Linear Volterra Integral Equations of the Second Kind”, TU J. Nat. Appl. Sci. , vol. 5, no. 1, pp. 121–133, Jan. 2023, doi: 10.59167/tujnas.v5i5.1314.