Micula, Gheorghe, and Graeme Fairweather. “ Direct Numerical Spline Methods for First-Order Fredholm Integro-Differential Equations”. Rev. Anal. Numér. Théor. Approx. 22, no. 1 (February 1, 1993): 59–66. Accessed September 3, 2025. https://www.ictp.acad.ro/jnaat/journal/article/view/1993-vol22-no1-art5.