@article{MMO_1981_42_a4,
     author = {B. M. Levitan and M. Otelbaev},
     title = {Conditions for selfadjointness of the {Schr\"odinger} and {Dirac} operators},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {142--159},
     publisher = {mathdoc},
     volume = {42},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1981_42_a4/}
}