@article{SEDP_1990-1991____A22_0,
     author = {Cancelier, C. E. and Chemin, J. Y.},
     title = {Sous-ellipticit\'e d'op\'erateurs int\'egro-diff\'erentiels v\'erifiant le principe du maximum},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:22},
     pages = {1--10},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1990-1991},
     mrnumber = {1131595},
     zbl = {0742.35077},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1990-1991____A22_0/}
}