@incollection{AST_1973__2-3__69_0,
     author = {Baiocchi, C.},
     title = {Sur quelques probl\`emes \`a fronti\`ere libre},
     booktitle = {Colloque International C.N.R.S. sur les \'equations aux d\'eriv\'ees partielles lin\'eaires},
     series = {Ast\'erisque},
     pages = {69--85},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {2-3},
     year = {1973},
     mrnumber = {390551},
     zbl = {0297.76075},
     language = {fr},
     url = {http://archive.numdam.org/item/AST_1973__2-3__69_0/}
}