@article{DAN_1977_235_4_a10,
     author = {B. M. Levitan and M. Otelbaev},
     title = {On conditions for selfadjointness of the {Schr\"odinger} and {Dirac} operators},
     journal = {Doklady Akademii Nauk},
     pages = {768--771},
     publisher = {mathdoc},
     volume = {235},
     number = {4},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_235_4_a10/}
}