@article{DAN_1957_117_3_a3,
     author = {Z. I. Leibenzon},
     title = {On estimation of the eigenvalues of self-adjoint operators},
     journal = {Doklady Akademii Nauk},
     pages = {371--373},
     publisher = {mathdoc},
     volume = {117},
     number = {3},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_117_3_a3/}
}