@article{DE_1970_6_3_a21,
     author = {G. A. Los'},
     title = {A solution of the stability problem for a system of linear differential equations with $\pi $-periodic coefficients by means of the $\pi /4$-characteristic equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {565--568},
     publisher = {mathdoc},
     volume = {6},
     number = {3},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1970_6_3_a21/}
}