@article{DAN_1958_121_1_a4,
     author = {V. M. Volosov},
     title = {Oscillation equations with slowly variable parameters},
     journal = {Doklady Akademii Nauk},
     pages = {22--25},
     year = {1958},
     volume = {121},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_121_1_a4/}
}