@article{MAN_1987__278_164297,
     author = {Thomas E. Cecil and Shiing-Shen Chern},
     title = {Tautness and {Lie} {Sphere} {Geometry.}},
     journal = {Mathematische Annalen},
     pages = {381--400},
     publisher = {mathdoc},
     volume = {278},
     year = {1987},
     zbl = {0635.53029},
     url = {http://geodesic.mathdoc.fr/item/MAN_1987__278_164297/}
}