@article{DAN_1980_254_4_a11,
     author = {I. M. Spitkovsky},
     title = {On block operators and related questions in the theory of factorization of matrix-valued functions},
     journal = {Doklady Akademii Nauk},
     pages = {816--820},
     publisher = {mathdoc},
     volume = {254},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1980_254_4_a11/}
}