@article{02221874, title = {Discrete Morse theory and graph braid groups.}, journal = {Geometry \& Topology}, volume = {5}, year = {2005}, pages = {1075-1109}, doi = {10.2140/agt.2005.5.1075}, zbl = {1134.20050}, language = {en}, url = {http://dml.mathdoc.fr/item/02221874} }
Farley, Daniel; Sabalka, Lucas. Discrete Morse theory and graph braid groups.. Geometry & Topology, Tome 5 (2005) pp. 1075-1109. doi : 10.2140/agt.2005.5.1075. http://gdmltest.u-ga.fr/item/02221874/