@article{PSMIR_1985___3_57_0,
     author = {Rodino, Luigi},
     title = {Analytic and {Gevrey} {Hypoellipticity}},
     journal = {Publications de l'Institut de recherche math\'ematiques de Rennes},
     pages = {57--88},
     publisher = {D\'epartement de Math\'ematiques et Informatique, Universit\'e de Rennes},
     number = {3},
     year = {1985},
     zbl = {0626.35017},
     language = {en},
     url = {http://archive.numdam.org/item/PSMIR_1985___3_57_0/}
}