@article{MZM_1987_41_2_a3,
     author = {A. S. Belov},
     title = {Coefficients of trigonometric series with nonnegative partial sums},
     journal = {Matemati\v{c}eskie zametki},
     pages = {152--158},
     publisher = {mathdoc},
     volume = {41},
     number = {2},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_2_a3/}
}