@article{DE_1984_20_11_a3,
     author = {N. S. Leonovich},
     title = {Classes of third-order systems without moving critical points},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1869--1877},
     publisher = {mathdoc},
     volume = {20},
     number = {11},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_11_a3/}
}