@article{DE_1968_4_9_a12,
     author = {I. V. Suveyka},
     title = {The exterior boundary value problem for an operator which decomposes into {Helmholtz} operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1667--1675},
     publisher = {mathdoc},
     volume = {4},
     number = {9},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_9_a12/}
}