YESSENBAYEVA, G.A.; YESBAYEV, A.N.; SYZDYKOVA, N.K.; SMIRNOVA, M.A. On the function approximation by trigonometric polynomials and the properties of families of function classes over harmonic intervals. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 111, n. 3, p. 181–190, 2023. DOI: 10.31489/2023m3/181-190. Disponível em: https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/592. Acesso em: 4 sep. 2025.