@article{DE_1996_32_8_a18,
     author = {V. S. Medvedev and E. L. Fedorov},
     title = {The number of limit cycles in dynamical systems close to {Hamiltonian} systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1140--1141},
     publisher = {mathdoc},
     volume = {32},
     number = {8},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1996_32_8_a18/}
}