@article{DAN_1964_155_4_a8,
     author = {A. S. Markus},
     title = {Some tests of completeness of the system of root vectors of a linear operator and the summability of series in that system},
     journal = {Doklady Akademii Nauk},
     pages = {753--756},
     publisher = {mathdoc},
     volume = {155},
     number = {4},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_155_4_a8/}
}