@article{DE_1974_10_12_a20,
     author = {S. M. Ponomarev},
     title = {A generalization of the theorem of {M.\,V.~Keldy{\v} s} on the completeness of the eigen- and associated functions of the first boundary value problem for a nonselfadjoint elliptic operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2294--2296},
     publisher = {mathdoc},
     volume = {10},
     number = {12},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_12_a20/}
}