@article{10_4171_ggd_228,
     author = {Lewis Bowen and Amos Nevo},
     title = {A horospherical ratio ergodic theorem for actions of free groups},
     journal = {Groups, geometry, and dynamics},
     pages = {331--353},
     year = {2014},
     volume = {8},
     number = {2},
     doi = {10.4171/ggd/228},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/228/}
}