@article{DE_1981_17_11_a3,
     author = {N. I. Vulpe},
     title = {The minimal basis of comitants of a differential system with quadratic nonlinearities},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1955--1963},
     publisher = {mathdoc},
     volume = {17},
     number = {11},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_11_a3/}
}