Bussamra, Flávio L.S., Paulo de Mattos Pimenta, and João A. Teixeira de Freitas. 2023. “Hybrid-Trefftz Stress Elements for Three-Dimensional Elastoplasticity”. Computer Assisted Methods in Engineering and Science 8 (2-3): 235-46. https://cames3.ippt.pan.pl/index.php/cames/article/view/1167.