@article{SM_1974_24_1_a6,
     author = {O. A. Oleinik and E. V. Radkevich},
     title = {Analyticity and theorems of {Liouville} and {Phragm\'en--Lindel\"of} type for general elliptic systems of differential equations},
     journal = {Sbornik. Mathematics},
     pages = {127--143},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {1974},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1974_24_1_a6/}
}