@article{DAN_1957_114_3_a8,
     author = {L. D. Nikolenko},
     title = {Some criteria for non-oscillation of a fourth order differential equation},
     journal = {Doklady Akademii Nauk},
     pages = {483--485},
     publisher = {mathdoc},
     volume = {114},
     number = {3},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_114_3_a8/}
}