@incollection{JEDP_1976____A10_0, author = {M\'etivier, Guy}, title = {Fonction spectrale et valeurs propres d'une classe d'op\'erateurs non elliptiques}, booktitle = {}, series = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, eid = {10}, pages = {1--54}, publisher = {Ecole polytechnique}, year = {1976}, language = {fr}, url = {http://www.numdam.org/item/JEDP_1976____A10_0/} }