@book{AST_1973__2-3_,
     author = {Collectif},
     title = {Colloque {International} {C.N.R.S.} sur les \'equations aux d\'eriv\'ees partielles lin\'eaires},
     series = {Ast\'erisque},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {2-3},
     year = {1973},
     language = {mul},
     url = {http://www.numdam.org/item/AST_1973__2-3_/}
}