J. Pamin and R. de Borst, “Stiffness degradation in gradient-dependent coupled damage-plasticity”, Arch. Mech., vol. 51, no. 3-4, pp. 419–446, Aug. 1999, Accessed: Mar. 02, 2026. [Online]. Available: https://am.ippt.pan.pl/index.php/am/article/view/v51p419