@article{GDZPPN00232394X,
title = {Isoparametric Hypersurfaces with Four or Six Distinct Principal Curvatures. Necessary Conditions on the Multiplicities.},
journal = {Mathematische Annalen},
volume = {264},
year = {1983},
pages = {283-302},
zbl = {0505.53027},
url = {http://dml.mathdoc.fr/item/GDZPPN00232394X}
}
Abresch, U. Isoparametric Hypersurfaces with Four or Six Distinct Principal Curvatures. Necessary Conditions on the Multiplicities.. Mathematische Annalen, Tome 264 (1983) pp. 283-302. http://gdmltest.u-ga.fr/item/GDZPPN00232394X/