Lifits S, Reutskiy S, Tirozzi B. Trefftz spectral method for initial-boundary problems. Comp. Assist. Methods Eng. Sci. [Internet]. 1997 Dec. 31 [cited 2026 Mar. 5];4(3-4):549-65. Available from: https://cames.ippt.gov.pl/index.php/cames/article/view/1389