@article{10_1090_S0894_0347_2011_00726_1,
     author = {Lewis, John and Nystr\~A{\textparagraph}m, Kaj},
     title = {Regularity and free boundary regularity for the {{\dh}‘-Laplace} operator in {Reifenberg} flat and {Ahlfors} regular domains},
     journal = {Journal of the American Mathematical Society},
     pages = {827--862},
     publisher = {mathdoc},
     volume = {25},
     number = {3},
     year = {2012},
     doi = {10.1090/S0894-0347-2011-00726-1},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-2011-00726-1/}
}