@article{DE_1971_7_11_a5,
     author = {L. B. Zelenko and F. S. Rofe-Beketov},
     title = {The limit spectrum of systems of first order differential equations with slowly changing coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1982--1991},
     publisher = {mathdoc},
     volume = {7},
     number = {11},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_11_a5/}
}