Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1975_11_5_a1, author = {N. A. Izobov}, title = {Half periods of the solutions of two-dimensional linear systems}, journal = {Differencialʹnye uravneni\^a}, pages = {782--797}, publisher = {mathdoc}, volume = {11}, number = {5}, year = {1975}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1975_11_5_a1/} }
N. A. Izobov. Half periods of the solutions of two-dimensional linear systems. Differencialʹnye uravneniâ, Tome 11 (1975) no. 5, pp. 782-797. http://geodesic.mathdoc.fr/item/DE_1975_11_5_a1/