@article{SEDP_1976-1977____A12_0,
     author = {Nourrigat, J.},
     title = {Param\'etrixes pour une classe d'op\'erateurs hypoelliptiques},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:13},
     pages = {1--9},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1976-1977},
     mrnumber = {477427},
     zbl = {0373.35057},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1976-1977____A12_0/}
}