Adeyemi S., O., O. M. Ogunlaran, and I. Adebisi A. “Numerical Solution of Volterra Integral Equation and Its Error Estimates Via Spectral Method”. American Academic Scientific Research Journal for Engineering, Technology, and Sciences, vol. 30, no. 1, Apr. 2017, pp. 47-56, https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/2507.