@article{GDZPPN002303302,
title = {On the Type Number of Hypersurfaces in Spaces of Constant Curvature.},
journal = {Mathematische Annalen},
volume = {189},
year = {1970},
pages = {310-316},
zbl = {0187.19202},
url = {http://dml.mathdoc.fr/item/GDZPPN002303302}
}
FERUS, D. On the Type Number of Hypersurfaces in Spaces of Constant Curvature.. Mathematische Annalen, Tome 189 (1970) pp. 310-316. http://gdmltest.u-ga.fr/item/GDZPPN002303302/