@article{DE_1997_33_4_a21,
     author = {N. B. Uskova},
     title = {Estimates for spectral expansions of the eigenvectors of some classes of perturbed differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {564--566},
     publisher = {mathdoc},
     volume = {33},
     number = {4},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1997_33_4_a21/}
}