@article{SEDP_1975-1976____A23_0,
     author = {Gourdin, D.},
     title = {Syst\`emes faiblement hyperboliques},
     journal = {S\'eminaire Goulaouic-Schwartz},
     note = {talk:22},
     pages = {1--21},
     year = {1975-1976},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     mrnumber = {473547},
     zbl = {0343.35055},
     language = {fr},
     url = {https://www.numdam.org/item/SEDP_1975-1976____A23_0/}
}