@article{DAN_1962_147_5_a9,
     author = {N. V. Marchenko},
     title = {On the extension of an operator and the existence of fixed points},
     journal = {Doklady Akademii Nauk},
     pages = {1026--1028},
     publisher = {mathdoc},
     volume = {147},
     number = {5},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_147_5_a9/}
}