@article{DAN_1975_222_1_a9,
     author = {\`E. M. Saak},
     title = {On the theory of multidimensional elliptic systems of first order},
     journal = {Doklady Akademii Nauk},
     pages = {43--46},
     publisher = {mathdoc},
     volume = {222},
     number = {1},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_222_1_a9/}
}