@article{DE_1978_14_6_a6,
     author = {M. N. Popa and K. S. Sibirskii},
     title = {Affine classification of a system with quadratic nonlinearities and not single valued canonical form},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1028--1033},
     publisher = {mathdoc},
     volume = {14},
     number = {6},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1978_14_6_a6/}
}