@article{SM_1967_2_4_a8,
     author = {M. A. Shubin},
     title = {Factorization of parameter-dependent matrix-functions in normed rings and certain related questions in the theory of noetherian operators},
     journal = {Sbornik. Mathematics},
     pages = {543--560},
     publisher = {mathdoc},
     volume = {2},
     number = {4},
     year = {1967},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1967_2_4_a8/}
}