@article{DAN_1982_267_2_a12,
     author = {V. A. Sadovnichii and B. E. Kanguzhin},
     title = {A connection between the spectrum of a differential operator with symmetric coefficients and the boundary conditions},
     journal = {Doklady Akademii Nauk},
     pages = {310--313},
     publisher = {mathdoc},
     volume = {267},
     number = {2},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1982_267_2_a12/}
}