@article{GDZPPN002296780, title = {Ergodic Theory and Virtual Groups.}, journal = {Mathematische Annalen}, volume = {163}, year = {1966}, pages = {187-207}, zbl = {0178.38802}, url = {http://dml.mathdoc.fr/item/GDZPPN002296780} }
MACKEY, G.W. Ergodic Theory and Virtual Groups.. Mathematische Annalen, Tome 163 (1966) pp. 187-207. http://gdmltest.u-ga.fr/item/GDZPPN002296780/