@article{DAN_1993_332_5_a4,
     author = {T. V. Savina},
     title = {On the reflection law for higher-order elliptic equations},
     journal = {Doklady Akademii Nauk},
     pages = {563--565},
     publisher = {mathdoc},
     volume = {332},
     number = {5},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1993_332_5_a4/}
}