@article{DE_1982_18_5_a5,
     author = {N. A. Izobov},
     title = {Sharp bounds of characteristic exponents of two-dimensional linear systems with bounded perturbations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {767--772},
     publisher = {mathdoc},
     volume = {18},
     number = {5},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1982_18_5_a5/}
}