@article{DAN_1964_156_4_a1,
     author = {A. V. Kuzhel'},
     title = {On the spectrum of a regular quasi-differential operator},
     journal = {Doklady Akademii Nauk},
     pages = {731--733},
     publisher = {mathdoc},
     volume = {156},
     number = {4},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_156_4_a1/}
}