@article{DE_1996_32_12_a18,
     author = {V. A. Krapivin and V. G. Romanovsky and A. V. Selitskii},
     title = {Center conditions for a six-parameter cubic system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1707--1709},
     publisher = {mathdoc},
     volume = {32},
     number = {12},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1996_32_12_a18/}
}