@article{TM_1997_216_a1,
     author = {V. I. Arnol'd},
     title = {Remarks on the {Morse} theory of a~divergence-free vector field, the averaging method, and the motion of a~charged particle in a~magnetic field},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {9--19},
     publisher = {mathdoc},
     volume = {216},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1997_216_a1/}
}