@article{RM_1964_19_2_a15,
     author = {V. Ya. Stetsenko},
     title = {On a method for estimating the spectrum of linear operator},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1964_19_2_a15/}
}