S. Lifits, S. Reutskiy, and B. Tirozzi, “Trefftz spectral method for initial-boundary problems”, CAMES, vol. 4, no. 3-4, pp. 549–565, Jun. 2023, Accessed: Apr. 19, 2025. [Online]. Available: https://cames3.ippt.pan.pl/index.php/cames/article/view/1389