H.-T. Huang, Z.-C. Li, and A. H.-D. Cheng, “Coupling techniques of Trefftz methods”, Comp. Assist. Methods Eng. Sci., vol. 15, no. 3-4, pp. 183–213, Jul. 2022, Accessed: Jun. 30, 2025. [Online]. Available: https://cames.ippt.pan.pl/index.php/cames/article/view/728