@article{DAN_1973_209_3_a2,
     author = {I. Gohberg and J. Laiterer},
     title = {A criterion for factorization of operator-functions with respect to a contour},
     journal = {Doklady Akademii Nauk},
     pages = {529--532},
     publisher = {mathdoc},
     volume = {209},
     number = {3},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_209_3_a2/}
}