@article{MZM_1983_34_6_a7,
     author = {V. G. Dolgolaptev},
     title = {Basicity of the root vectors of weakly perturbed operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {867--872},
     publisher = {mathdoc},
     volume = {34},
     number = {6},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1983_34_6_a7/}
}