@article{MAN_1970__187_162027,
     author = {D. FERUS},
     title = {On the {Type} {Number} of {Hypersurfaces} in {Spaces} of {Constant} {Curvature.}},
     journal = {Mathematische Annalen},
     pages = {310--316},
     publisher = {mathdoc},
     volume = {187},
     year = {1970},
     zbl = {0187.19202},
     url = {http://geodesic.mathdoc.fr/item/MAN_1970__187_162027/}
}