W. Wojno, “Solution for an Irregular Perturbation Problem of Viscoplastic Spherical Container Under Internal Pressure”, Eng. Trans., vol. 41, no. 2, pp. 209–235, Jul. 1993, Accessed: Jul. 14, 2025. [Online]. Available: https://et.ippt.pan.pl/index.php/et/article/view/1565