@article{JEDP_1975____251_0,
     author = {Nourrigat, Jean-Fran\c{c}ois},
     title = {Probl\`emes mixtes pour des syst\`emes hyperboliques singuliers},
     journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     pages = {251--261},
     publisher = {Ecole polytechnique},
     year = {1975},
     mrnumber = {509847},
     language = {fr},
     url = {http://archive.numdam.org/item/JEDP_1975____251_0/}
}