Teixeira de Freitas, João A., and Corneliu Cismaşiu. “Developments With Hybrid-Trefftz Stress and Displacement Elements”. Computer Assisted Methods in Engineering and Science 8, no. 2-3 (September 30, 2001): 289–311. Accessed March 5, 2026. https://cames.ippt.gov.pl/index.php/cames/article/view/1171.