@article{SM_1976_28_3_a1,
     author = {S. A. Smagin},
     title = {Complex powers of hypoelliptic systems in~$\mathbf R^n$},
     journal = {Sbornik. Mathematics},
     pages = {291--300},
     publisher = {mathdoc},
     volume = {28},
     number = {3},
     year = {1976},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1976_28_3_a1/}
}