@article{MZM_1990_48_5_a0,
     author = {V. A. Andrienko},
     title = {Rate of approximation of orthogonal series by {Riesz} means},
     journal = {Matemati\v{c}eskie zametki},
     pages = {3--14},
     publisher = {mathdoc},
     volume = {48},
     number = {5},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_5_a0/}
}