1. P. L. Ul’yanov, “Embedding Theorems and Relations Between the Best Approximations (Moduli of Continuity) in Different Metrics,” Matem. Sbornik 81(123)(1), 104 (1970).
2. M. K. Potapov and B. V. Simonov, “Relations Between Moduli of Smoothness in Different Metrics,” Vestn. Mosk. Univ., Matem. Mekhan., No 3, 17 (2009).
3. M. K. Potapov, B. V. Simonov, and S. Yu. Tikhonov, “Mixed Moduli of Smoothness in L
p, 1 < p < ∞: A Survey,” Surveys in Approximation Theory 8, 1 (2013).
4. Vol. X: Mathematics. Issue 2 (to 100th anniversary of Luzin’s seminar on the theory of functions.);M K Potapov,2015
5. O. V. Besov, V. P. Il’in, and S. M. Nikol’skii, Integral Representation of Functions and Embedding Theorems (Nauka, Moscow, 1975) [in Russian].