@article{DE_1989_25_1_a15,
     author = {A. P. Soldatov},
     title = {Higher-order elliptic systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {136--144},
     publisher = {mathdoc},
     volume = {25},
     number = {1},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_1_a15/}
}