Gunes, Baransel, and Musa Cakir. “A Fitted Approximate Method for Solving Singularly Perturbed Volterra–Fredholm Integro-Differential Equations With an Integral Boundary Condition”. Ukrains’kyi Matematychnyi Zhurnal 76, no. 1 (February 2, 2024): 115–131. Accessed April 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/7331.