@article{JEMS_2010_12_2_a3,
     author = {Michael Hochman},
     title = {A ratio ergodic theorem for multiparameter non-singular actions},
     journal = {Journal of the European Mathematical Society},
     pages = {365--383},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {2010},
     doi = {10.4171/jems/201},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/201/}
}