@article{SIGMA_2014_10_a59,
     author = {Paul F. Baum and Piotr M. Hajac},
     title = {Local {Proof} of {Algebraic} {Characterization} of {Free} {Actions}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2014},
     volume = {10},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2014_10_a59/}
}