@article{SEDP_1970-1971____A12_0,
     author = {Derridj, M.},
     title = {Sur une classe d'op\'erateurs diff\'erentiels hypoelliptiques \`a coefficients analytiques},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:12},
     pages = {1--6},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1970-1971},
     mrnumber = {407433},
     zbl = {0234.35020},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1970-1971____A12_0/}
}