@article{02057405,
title = {Combination of convergence groups.},
journal = {Geometry \& Topology},
volume = {7},
year = {2003},
pages = {933-963},
doi = {10.2140/gt.2003.7.933},
zbl = {1037.20042},
language = {en},
url = {http://dml.mathdoc.fr/item/02057405}
}
Dahmani, François. Combination of convergence groups.. Geometry & Topology, Tome 7 (2003) pp. 933-963. doi : 10.2140/gt.2003.7.933. http://gdmltest.u-ga.fr/item/02057405/