@article{MAN_1986__276_164197,
     author = {Nessim Sibony},
     title = {Hypoellipticit\'e pour l'op\'erateur ... .},
     journal = {Mathematische Annalen},
     pages = {279--290},
     publisher = {mathdoc},
     volume = {276},
     year = {1986},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/MAN_1986__276_164197/}
}