@article{DAN_1990_315_1_a4,
     author = {A. V. Pechenev},
     title = {Averaging of systems with hierarchy of phase rotation speeds on},
     journal = {Doklady Akademii Nauk},
     pages = {28--31},
     publisher = {mathdoc},
     volume = {315},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_315_1_a4/}
}