@article{DE_1968_4_4_a4,
     author = {G. A. Los'},
     title = {Theorems on the instability of solutions of an $n$th order linear homogeneous differential equation with periodic coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {625--630},
     publisher = {mathdoc},
     volume = {4},
     number = {4},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_4_a4/}
}