@article{DE_1990_26_6_a2,
     author = {N. A. Izobov and O. P. Stepanovich},
     title = {Exponentially decreasing perturbations that preserve the characteristic exponents of a linear diagonal system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {934--943},
     publisher = {mathdoc},
     volume = {26},
     number = {6},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_6_a2/}
}