@article{DE_1993_29_2_a7,
     author = {N. L. Shcheglova},
     title = {Investigation of systems with homogeneous cubic nonlinearities that have a focus and a center},
     journal = {Differencialʹnye uravneni\^a},
     pages = {246--255},
     publisher = {mathdoc},
     volume = {29},
     number = {2},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_2_a7/}
}