@article{SM_1967_3_1_a6,
     author = {G. K. Lebed'},
     title = {Trigonometric series with coefficients satisfying certain conditions},
     journal = {Sbornik. Mathematics},
     pages = {91--108},
     year = {1967},
     volume = {3},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1967_3_1_a6/}
}