@incollection{SB_1991-1992__34__7_0,
     author = {Bellissard, Jean},
     title = {Le papillon de {Hofstadter}},
     booktitle = {S\'eminaire Bourbaki : volume 1991/92, expos\'es 745-759},
     series = {Ast\'erisque},
     note = {talk:745},
     pages = {7--39},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {206},
     year = {1992},
     mrnumber = {1206063},
     zbl = {0791.46057},
     language = {fr},
     url = {http://archive.numdam.org/item/SB_1991-1992__34__7_0/}
}