@article{GDZPPN002083795,
title = {On the Dirichlet Problem at Infinity for Manifolds of Nonpositive Curvature.},
journal = {Forum mathematicum},
volume = {1},
year = {1989},
pages = {201-214},
zbl = {0661.53026},
url = {http://dml.mathdoc.fr/item/GDZPPN002083795}
}
Ballmann, Werner. On the Dirichlet Problem at Infinity for Manifolds of Nonpositive Curvature.. Forum mathematicum, Tome 1 (1989) pp. 201-214. http://gdmltest.u-ga.fr/item/GDZPPN002083795/