@article{DE_1971_7_12_a1,
     author = {N. A. Izobov},
     title = {The canonical form of a linear two-dimensional system with variable coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2136--2142},
     publisher = {mathdoc},
     volume = {7},
     number = {12},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_12_a1/}
}