@article{DAN_1989_309_5_a6,
     author = {Yu. E. Karpeshina},
     title = {Perturbation theory for the {Schr\"odinger} operator with periodic nonsmooth potential},
     journal = {Doklady Akademii Nauk},
     pages = {1055--1059},
     publisher = {mathdoc},
     volume = {309},
     number = {5},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_309_5_a6/}
}