Stepanets, O. I. 2004. “Best Approximations of $q$-Ellipsoids in Spaces $S_{ϕ}^{p,μ}$”. Ukrains’kyi Matematychnyi Zhurnal 56 (10): 1378-83. https://umj.imath.kiev.ua/index.php/umj/article/view/3850.