@article{DE_1984_20_2_a1,
     author = {E. A. Barabanov},
     title = {The highest $\sigma $-exponent of linear differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {197--207},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_2_a1/}
}