@book{AST_1983__46__1_0,
     author = {Serre, Jean-Pierre},
     title = {Arbres, amalgames, $SL_2$},
     series = {Ast\'erisque},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {46},
     year = {1977},
     mrnumber = {476875},
     zbl = {0369.20013},
     language = {fr},
     url = {http://archive.numdam.org/item/AST_1983__46__1_0/}
}