Cherneі N. I., “Criterion of stable convexity of a region in one-sheeted conformal mappings. I ”, Ukr. Mat. Zhurn., vol. 18, no. 1, pp. 86–91, Jan. 1966, Accessed: Apr. 07, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8655