@article{02104400,
title = {Foldable cubical complexes of nonpositive curvature.},
journal = {Geometry \& Topology},
volume = {8},
year = {2004},
pages = {603-622},
doi = {10.2140/agt.2004.4.603},
zbl = {1055.20035},
language = {en},
url = {http://dml.mathdoc.fr/item/02104400}
}
Xie, Xiangdong. Foldable cubical complexes of nonpositive curvature.. Geometry & Topology, Tome 8 (2004) pp. 603-622. doi : 10.2140/agt.2004.4.603. http://gdmltest.u-ga.fr/item/02104400/