Sladek Vladimίr, Ján Sladek, and Roger van Keer. “New Integral Equation Approach to Solution of Diffusion Equation”. Computer Assisted Methods in Engineering and Science 9, no. 4 (December 31, 2002): 555–572. Accessed March 5, 2026. https://cames.ippt.gov.pl/index.php/cames/article/view/1118.