@article{VMUMM_1993_4_a21,
     author = {S. L. Dudoladov},
     title = {Periodic solutions near resonance equilibrium of conservative systems},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {87--89},
     year = {1993},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1993_4_a21/}
}