@article{IM2_1997_61_2_a2,
     author = {E. A. Kalita},
     title = {Solubility of non-linear elliptic systems in spaces that are weaker than the natural energy space},
     journal = {Izvestiya. Mathematics },
     pages = {285--315},
     publisher = {mathdoc},
     volume = {61},
     number = {2},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_2_a2/}
}