@article{MS2_1994__74_1_167294,
     author = {J. Verdera and P.V. Paramonov},
     title = {Approximation by {Solutions} of {Elliptic} {Equations} on {Closed} {Subsets} of {Euclidean} {Space.}},
     journal = {Mathematica Scandinavica},
     pages = {249--259},
     publisher = {mathdoc},
     volume = {74},
     number = {1},
     year = {1994},
     zbl = {0835.35035},
     url = {http://geodesic.mathdoc.fr/item/MS2_1994__74_1_167294/}
}