@article{DE_1997_33_1_a3,
     author = {V. D. Budaev},
     title = {On {Hilbert} and {Bessel} inequalities for some sine, cosine and exponential systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {19--24},
     publisher = {mathdoc},
     volume = {33},
     number = {1},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1997_33_1_a3/}
}