@article{DAN_1981_261_3_a8,
     author = {F. S. Rofe-Beketov and A. M. Khol'kin},
     title = {The connection between spectral and oscillatory properties of differential systems of arbitrary order},
     journal = {Doklady Akademii Nauk},
     pages = {551--555},
     publisher = {mathdoc},
     volume = {261},
     number = {3},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1981_261_3_a8/}
}