@article{DE_1977_13_12_a17,
     author = {M. N. Popa},
     title = {Syzygies between the affine invariants of a system with quadratic right hand sides},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2272--2275},
     publisher = {mathdoc},
     volume = {13},
     number = {12},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_12_a17/}
}