@article{SEDP_1979-1980____A13_0,
     author = {Baouendi, M. S. and M\'etivier, G.},
     title = {Vecteurs analytiques d'op\'erateurs hypoelliptiques et de type principal},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:12},
     pages = {1--13},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1979-1980},
     zbl = {0447.35024},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1979-1980____A13_0/}
}