PONTER, A.R.S.; CHEN, H.F. Direct methods for limits in plasticity. Archives of Mechanics, Warsaw, Poland, v. 57, n. 2-3, p. 171–187, 2005. Disponível em: https://am.ippt.pan.pl/index.php/am/article/view/v57p171. Acesso em: 19 nov. 2025.