@incollection{AST_1973__2-3__217_0,
     author = {Ikawa, Mitsuru},
     title = {Remarques sur les probl\`emes mixtes pour l'\'equation des ondes},
     booktitle = {Colloque International C.N.R.S. sur les \'equations aux d\'eriv\'ees partielles lin\'eaires},
     series = {Ast\'erisque},
     pages = {217--221},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {2-3},
     year = {1973},
     mrnumber = {447814},
     zbl = {0284.35037},
     language = {fr},
     url = {http://www.numdam.org/item/AST_1973__2-3__217_0/}
}