Serdyuk АS, Stepaniuk Т. Estimates of the best orthogonal trigonometric approximations of the classes of convolutions of periodic functions of not high smoothness . Dopov. Nac. akad. nauk Ukr. [Internet]. 2025 Feb. 5 [cited 2025 Jun. 1];(7):13-9. Available from: https://nasu-periodicals.org.ua/index.php/dp/article/view/15066