@article{MZM_2011_90_2_a16,
     author = {O. P. Filatov},
     title = {Averaging {Theorem} for {Indeterminate} {Conditionally} {Periodic} {Motion}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {318--320},
     publisher = {mathdoc},
     volume = {90},
     number = {2},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2011_90_2_a16/}
}