@article{SEDP_1972-1973____A8_0,
     author = {Duistermaat, J. J. and Sjostrand, J.},
     title = {Sur une classe d'op\'erateurs de type sous-elliptique},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:7},
     pages = {1--13},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1972-1973},
     zbl = {0272.35060},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1972-1973____A8_0/}
}