Moldovan, Ionut D., and Joan A. Teixeira de Freitas. “Hybrid-Trefftz Stress and Displacement Elements for Dynamic Analysis of Bounded and Unbounded Saturated Porous Media”. Computer Assisted Methods in Engineering and Science 15, no. 3-4 (December 31, 2008): 289–303. Accessed May 8, 2026. http://cames.ippt.gov.pl/index.php/cames/article/view/737.