@article{MZ_1982__181_173255,
     author = {Dirk Ferus},
     title = {The {Tightness} of {Extrinsic} {Symmetric} {Submanifolds.}},
     journal = {Mathematische Zeitschrift},
     pages = {563--566},
     year = {1982},
     volume = {181},
     zbl = {0488.53041},
     url = {http://geodesic.mathdoc.fr/item/MZ_1982__181_173255/}
}