@article{DE_1976_12_5_a17,
     author = {A. G. Ramm},
     title = {A boundary value problem with a discontinuous boundary condition},
     journal = {Differencialʹnye uravneni\^a},
     pages = {931--933},
     publisher = {mathdoc},
     volume = {12},
     number = {5},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_5_a17/}
}