@article{DAN_1969_184_3_a7,
     author = {I. B. Ledovskaya},
     title = {The higher order approximations of {N.} {N.~Bogoljubov} and {N.} {M.~Krylov} for solutions bounded on the whole axis},
     journal = {Doklady Akademii Nauk},
     pages = {538--541},
     year = {1969},
     volume = {184},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_184_3_a7/}
}