Indefinite affine hyperspheres admitting a pointwise symmetry. II. Scharlach, Christine — 2009 SIGMA. Symmetry, Integrability and Geometry: Methods and Applications [electronic only]
Indefinite affine hyperspheres admitting a pointwise symmetry. I. Scharlach, Christine — 2007 Beiträge zur Algebra und Geometrie
A new intrinsic curvature invariant for centroaffine hypersurfaces. Scharlach, Christine; Simon, Udo; Verstraelen, Leopold; Vrancken, Luc — 1997 Beiträge zur Algebra und Geometrie