OHNIMUS, Stephan; RÜTER, Marcus; STEIN, Erwin. General aspects of Trefftz method and relations to error estimation of finite element approximations. Computer Assisted Methods in Engineering and Science, [S. l.], v. 8, n. 2-3, p. 425–437, 2023. Disponível em: https://cames3.ippt.pan.pl/index.php/cames/article/view/1180. Acesso em: 12 jan. 2025.