@article{JEDP_1979____A10_0, author = {Helffer, Bernard and Nourrigat, Jean}, title = {Hypoellipticit\'e pour des op\'erateurs quasi-homog\`enes \`a coefficients polynomiaux}, journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, eid = {10}, publisher = {Ecole polytechnique}, year = {1979}, zbl = {0405.35024}, mrnumber = {83c:35026}, language = {fr}, url = {http://archive.numdam.org/item/JEDP_1979____A10_0/} }