@article{DAN_1964_159_2_a1,
     author = {V. F. Gaposhkin},
     title = {On the convergence of orthogonal series},
     journal = {Doklady Akademii Nauk},
     pages = {243--246},
     publisher = {mathdoc},
     volume = {159},
     number = {2},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_159_2_a1/}
}