Kogan AM. On the best approximation of classes $W^r H^{ω}$ by algebraic polynomials in the space $L_1$. Ukr. Mat. Zhurn. [Internet]. 1999Nov.25 [cited 2024May18];51(11):1456-6. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4747