Konkol, F., and V. Kompis. “Trefftz Polynomials Reciprocity Based Boundary Element Formulations for Elastodynamics”. Computer Assisted Methods in Engineering and Science 11, no. 2-3 (September 30, 2004): 239–245. Accessed March 5, 2026. https://cames.ippt.gov.pl/index.php/cames/article/view/1037.