H. Sanecki and A. P. Zieliński, “The Trefftz finite elements modelling crack propagation”, Comp. Assist. Methods Eng. Sci., vol. 15, no. 3-4, pp. 353–368, Jul. 2022, Accessed: Jun. 30, 2025. [Online]. Available: https://cames.ippt.pan.pl/index.php/cames/article/view/742