@article{DE_1977_13_12_a16,
     author = {B.-W. Schulze},
     title = {The inverse problem for higher order elliptic equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2265--2271},
     publisher = {mathdoc},
     volume = {13},
     number = {12},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_12_a16/}
}