Stankiewicz, Anna, and Jerzy Pamin. “Simulation of Instabilities in Non-Softening Drucker-Prager Plasticity”. Computer Assisted Methods in Engineering and Science, vol. 8, no. 1, Mar. 2023, pp. 183-04, https://cames3.ippt.pan.pl/index.php/cames/article/view/1199.