@article{DAN_1958_118_3_a0,
     author = {I. M. Glazman},
     title = {Oscillation theorems for differential equations of higher orders and the spectrum of the respective differential operators},
     journal = {Doklady Akademii Nauk},
     pages = {423--426},
     publisher = {mathdoc},
     volume = {118},
     number = {3},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_118_3_a0/}
}