@article{DE_1980_16_3_a6,
     author = {I. N. Sergeev},
     title = {Sharp upper bounds of mobility of the {Ljapunov} exponents of a system of differential equations and the behavior of the exponents under perturbations approaching},
     journal = {Differencialʹnye uravneni\^a},
     pages = {438--448},
     publisher = {mathdoc},
     volume = {16},
     number = {3},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_3_a6/}
}