@article{GDZPPN002321815,
title = {Axial Isometries of Manifolds of Non-Positive Curvature.},
journal = {Mathematische Annalen},
volume = {261},
year = {1982},
pages = {131-144},
zbl = {0487.53039},
url = {http://dml.mathdoc.fr/item/GDZPPN002321815}
}
Ballmann, Werner. Axial Isometries of Manifolds of Non-Positive Curvature.. Mathematische Annalen, Tome 261 (1982) pp. 131-144. http://gdmltest.u-ga.fr/item/GDZPPN002321815/