SZEPTYŃSKI, P. “Yield Criterion Accounting for the Influence of the Third Invariant of Stress Tensor Deviator. Part II. Analysis of Convexity Condition of the Yield Surface”. Engineering Transactions 59, no. 4 (December 31, 2011): 283–297. Accessed March 19, 2026. https://et.ippt.gov.pl/index.php/et/article/view/139.