@article{DE_1975_11_12_a25,
     author = {V. I. Filippenko},
     title = {Estimation of the multiplicity of the spectrum of a selfadjoint differential operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2286--2287},
     publisher = {mathdoc},
     volume = {11},
     number = {12},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_12_a25/}
}