@article{DE_1992_28_5_a23,
     author = {V. V. Karachik},
     title = {Solvability of a boundary value problem for the {Helmholtz} equation with higher-order normal derivatives on the boundary},
     journal = {Differencialʹnye uravneni\^a},
     pages = {907--909},
     publisher = {mathdoc},
     volume = {28},
     number = {5},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1992_28_5_a23/}
}