@article{GDZPPN002101289, title = {A splitting theorem for spaces of nonpositive curvature.}, journal = {Inventiones mathematicae}, volume = {82}, year = {1985}, pages = {323-328}, zbl = {0543.53036}, url = {http://dml.mathdoc.fr/item/GDZPPN002101289} }
Schroeder, Viktor. A splitting theorem for spaces of nonpositive curvature.. Inventiones mathematicae, Tome 82 (1985) pp. 323-328. http://gdmltest.u-ga.fr/item/GDZPPN002101289/