@article{DE_1982_18_2_a4,
     author = {N. I. Gavrilov},
     title = {On the stability of solutions of a class of {Hamiltonian} systems with small changes of the function $H$},
     journal = {Differencialʹnye uravneni\^a},
     pages = {219--234},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1982_18_2_a4/}
}