@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/}
}