@article{PFMT_2011_1_a3,
     author = {V. N. Kapshai and L. D. Korsun},
     title = {The stationary perturbation theory in case of a potential-series},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {29--35},
     publisher = {mathdoc},
     number = {1},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2011_1_a3/}
}