@article{IM_1988__92_1_143564,
     author = {So-Chin Chen},
     title = {Global analytic hypoellipticity of the {?-Neumann} problem on circular domains.},
     journal = {Inventiones mathematicae},
     pages = {173--186},
     publisher = {mathdoc},
     volume = {92},
     number = {1},
     year = {1988},
     url = {http://geodesic.mathdoc.fr/item/IM_1988__92_1_143564/}
}