@article{RM_1963_18_2_a13,
     author = {I. Ts. Gokhberg},
     title = {Factorization of operator functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1963_18_2_a13/}
}