@article{GDZPPN002486865,
title = {Isometric Reflections with Respect to Submanifolds and the Ricci Operator of Geodesic Spheres.},
journal = {Monatshefte f\"ur Mathematik},
volume = {108},
year = {1989},
pages = {211-218},
zbl = {0712.53023},
url = {http://dml.mathdoc.fr/item/GDZPPN002486865}
}
Tondeur, Philippe; Vanhecke, Lieven. Isometric Reflections with Respect to Submanifolds and the Ricci Operator of Geodesic Spheres.. Monatshefte für Mathematik, Tome 108 (1989) pp. 211-218. http://gdmltest.u-ga.fr/item/GDZPPN002486865/