@article{RM_1963_18_1_a10,
     author = {Yu. I. Lyubich},
     title = {Completeness conditions for a~system of eigenvectors of a~correct operator},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {18},
     number = {1},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1963_18_1_a10/}
}