@article{DE_1977_13_11_a13,
     author = {V. A. Sadovnichy and V. V. Dubrovskii},
     title = {Some relations for the eigenvalues of discrete operators. {Trace} formulas for partial differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2033--2042},
     publisher = {mathdoc},
     volume = {13},
     number = {11},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_11_a13/}
}