@article{FAA_2009_43_3_a4,
     author = {R. S. Ismagilov and A. G. Kostyuchenko},
     title = {Perturbation of the {Spectrum} of a {Differential} {Operator} under a {Bounded} {Perturbation} of the {Potential}},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {54--64},
     publisher = {mathdoc},
     volume = {43},
     number = {3},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_2009_43_3_a4/}
}