@article{TIMM_2003_9_1_a11,
     author = {L. A. Kalyakin},
     title = {Justification of asymptotic expansions for the principal resonance equations},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {88--101},
     year = {2003},
     volume = {9},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_2003_9_1_a11/}
}