Ohnimus, S., 		Rüter, M., & 		Stein, E.
(2023).
 General aspects of Trefftz method and relations to error estimation of finite element approximations.
<em>Computer Assisted Methods In Engineering And Science, 8</em>(2-3), 425-437.
Retrieved from <a href="https://cames.ippt.pan.pl/index.php/cames/article/view/1180" target="_new">https://cames.ippt.pan.pl/index.php/cames/article/view/1180</a>