@article{MAN_1978__238_163192,
     author = {Klaus J\"anich},
     title = {Symmetry {Properties} of {Singularities} of {C{\textdegree}{\textdegree}-Functions.}},
     journal = {Mathematische Annalen},
     pages = {147--156},
     publisher = {mathdoc},
     volume = {238},
     year = {1978},
     zbl = {0384.58011},
     url = {http://geodesic.mathdoc.fr/item/MAN_1978__238_163192/}
}