@article{DAN_1975_225_6_a9,
     author = {V. I. Shevchenko},
     title = {On the homotopy classification of {Douglis--Nirenberg} elliptic systems},
     journal = {Doklady Akademii Nauk},
     pages = {1275--1277},
     publisher = {mathdoc},
     volume = {225},
     number = {6},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_225_6_a9/}
}