@article{IM_1993__113_2_144134,
     author = {Carlos E. Kenig and Jill Pipher},
     title = {The {Neumann} problem for elliptic equations with non-smooth coefficients.},
     journal = {Inventiones mathematicae},
     pages = {447--510},
     publisher = {mathdoc},
     volume = {113},
     number = {2},
     year = {1993},
     zbl = {0807.35030},
     url = {http://geodesic.mathdoc.fr/item/IM_1993__113_2_144134/}
}