Winnicki, I., M. Kleiber, and M. Kwieciński. “Finite Element Analysis of Elastic-Plastic Plane Stress Problem”. Engineering Transactions 23, no. 4 (December 30, 1975): 609–624. Accessed June 9, 2025. https://et3.ippt.pan.pl/index.php/et/article/view/2381.