@article{DE_1989_25_3_a3,
     author = {F. G. Maksudov and O. A. Veliev},
     title = {Spectral analysis of differential operators with periodic matrix coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {400--409},
     publisher = {mathdoc},
     volume = {25},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_3_a3/}
}