@article{02237562,
title = {Two special simply connected spaces of nonpositive curvature.},
journal = {Sibirskij Matematicheskij Zhurnal},
volume = {44},
year = {2003},
pages = {1033-1040},
zbl = {1080.53027},
language = {en},
url = {http://dml.mathdoc.fr/item/02237562}
}
Ionin, V.K. Two special simply connected spaces of nonpositive curvature.. Sibirskij Matematicheskij Zhurnal, Tome 44 (2003) pp. 1033-1040. http://gdmltest.u-ga.fr/item/02237562/