@article{DAN_1994_338_1_a9,
     author = {V. P. Sakhnenko and G. M. Chechin},
     title = {Groups of modes and normal oscillations for nonlinear dynamical},
     journal = {Doklady Akademii Nauk},
     pages = {42--45},
     publisher = {mathdoc},
     volume = {338},
     number = {1},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1994_338_1_a9/}
}