@article{10_4171_ggd_161,
     author = {Simon Thomas},
     title = {Universal {Borel} actions of countable groups},
     journal = {Groups, geometry, and dynamics},
     pages = {389--407},
     year = {2012},
     volume = {6},
     number = {2},
     doi = {10.4171/ggd/161},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/161/}
}