@article{DAN_1987_293_3_a5,
     author = {M. Rakhimov},
     title = {On the property of being a {Riesz} basis of systems of eigen- and},
     journal = {Doklady Akademii Nauk},
     pages = {538--540},
     publisher = {mathdoc},
     volume = {293},
     number = {3},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_293_3_a5/}
}