T. Skiepko, “Heat transmission across fouled tubes analysed by Trefftz approach”, Comp. Assist. Methods Eng. Sci., vol. 9, no. 2, pp. 239–269, Jun. 2002, Accessed: Feb. 23, 2026. [Online]. Available: https://cames.ippt.pan.pl/index.php/cames/article/view/1133