Babenko, V. F., et al. “Kolmogorov-Type Inequalities for Mixed Derivatives of Functions of Many Variables”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 56, no. 5, May 2004, pp. 579-94,
https://umj.imath.kiev.ua/index.php/umj/article/view/3779
.