Vyhovs'ka, I.Y. and Zelinskii, Y.B. (2008) “Criterion for convexity of a domain of a Euclidean space”,
Ukrains’kyi Matematychnyi Zhurnal, 60(5), pp. 709–711. Available at:
https://umj.imath.kiev.ua/index.php/umj/article/view/3189 (Accessed: 10 April 2025).