@article{MZ_1977__153_172476,
     author = {Udo Simon},
     title = {Isometries with {Spheres.}},
     journal = {Mathematische Zeitschrift},
     pages = {23--28},
     publisher = {mathdoc},
     volume = {153},
     year = {1977},
     zbl = {0326.53053},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__153_172476/}
}