@article{EJDE_1997__1997__a30,
     author = {Adams, D.R. and Nussenzveig Lopes, H.J.},
     title = {Nonlinear weakly elliptic $2\times 2$ systems of variational inequalities with unilateral obstacle constraints},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {1997},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_1997__1997__a30/}
}