@article{TMF_1971_9_2_a6,
     author = {T. M. Gataullin and M. V. Karasev},
     title = {On the perturbation of the quasilevels of {a~Schr\"odinger} operator with complex potential},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {252--263},
     publisher = {mathdoc},
     volume = {9},
     number = {2},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1971_9_2_a6/}
}