@article{AM_1999_150_2_a0,
     author = {Carlos E. Kenig and Tatiana Toro},
     title = {Free boundary regularity for harmonic measures and {Poisson} kernels},
     journal = {Annals of mathematics},
     publisher = {mathdoc},
     volume = {150},
     number = {2},
     year = {1999},
     url = {http://geodesic.mathdoc.fr/item/AM_1999_150_2_a0/}
}