@article{DE_1987_23_6_a20,
     author = {S. Ya. L'vin},
     title = {Overdetermined boundary value problems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1081--1084},
     publisher = {mathdoc},
     volume = {23},
     number = {6},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1987_23_6_a20/}
}