@article{DAN_1975_225_6_a0,
     author = {Yu. N. Bibikov},
     title = {An application of a theorem of {Moser} to the investigation of differential equations of nonlinear oscillations},
     journal = {Doklady Akademii Nauk},
     pages = {1241--1244},
     publisher = {mathdoc},
     volume = {225},
     number = {6},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_225_6_a0/}
}