@article{SEDP_1970-1971____A20_0,
     author = {Rondeau},
     title = {Condition n\'ecessaire et suffisante d'hyperbolicit\'e},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:20},
     pages = {1--11},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1970-1971},
     zbl = {0237.35057},
     language = {fr},
     url = {http://www.numdam.org/item/SEDP_1970-1971____A20_0/}
}