O. A. Emets, “Extremal properties of nondifferentiable convex functions on euclidean sets of combinations with repetitions”, Ukr. Mat. Zhurn., vol. 46, no. 6, pp. 680–691, Jun. 1994, Accessed: Dec. 15, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5695