@article{10_2140_agt_2011_11_1737,
     author = {Putman, Andrew},
     title = {Obtaining presentations from group actions without making choices},
     journal = {Algebraic and Geometric Topology},
     pages = {1737--1766},
     year = {2011},
     volume = {11},
     number = {3},
     doi = {10.2140/agt.2011.11.1737},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2011.11.1737/}
}