@article{GDZPPN002236400,
title = {Totally geodesic hypersurfaces in manifolds of nonpositive curvature.},
journal = {Manuscripta mathematica},
volume = {86},
year = {1995},
pages = {169-184},
zbl = {0830.53034},
url = {http://dml.mathdoc.fr/item/GDZPPN002236400}
}
Schroeder, Viktor; Goette, Sebastian. Totally geodesic hypersurfaces in manifolds of nonpositive curvature.. Manuscripta mathematica, Tome 86 (1995) pp. 169-184. http://gdmltest.u-ga.fr/item/GDZPPN002236400/