@article{DAN_1963_150_6_a3,
     author = {M. G. Gasymov},
     title = {On the sum of the differences of the eigenvalues of two self-adjoint operators},
     journal = {Doklady Akademii Nauk},
     pages = {1202--1205},
     publisher = {mathdoc},
     volume = {150},
     number = {6},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_150_6_a3/}
}