@article{DE_1967_3_3_a12,
     author = {M. M. Gekhtman and A. G. Kostyuchenko},
     title = {Complex eigenvalues of a non-selfadjoint operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {509--513},
     publisher = {mathdoc},
     volume = {3},
     number = {3},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1967_3_3_a12/}
}