@article{DM_1990_2_2_a2,
     author = {I. I. Sharapudinov},
     title = {Approximation properties of discrete {Fourier} sums},
     journal = {Diskretnaya Matematika},
     pages = {33--44},
     year = {1990},
     volume = {2},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_1990_2_2_a2/}
}