@article{EJDE_1994__1994_7_a0,
     author = {Costa,  David G.},
     title = {On a class of elliptic systems in \(\mathbb {R^n\)}},
     journal = {Electronic journal of differential equations},
     year = {1994},
     volume = {1994},
     number = {7},
     zbl = {0809.35020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_1994__1994_7_a0/}
}