V. M. Leitão, “Comparison of Galerkin and collocation Trefftz formulations for plane elasticity”, Comp. Assist. Methods Eng. Sci., vol. 8, no. 2-3, pp. 397–407, Mar. 2023, Accessed: Jun. 30, 2025. [Online]. Available: https://cames.ippt.pan.pl/index.php/cames/article/view/1178