@article{JEMS_2008_10_4_a4,
     author = {Jean Bourgain and Alex Gamburd},
     title = {Expansion and random walks in $\mathrm{SL}_d(\mathbb{Z}/p^n\mathbb{\ensuremath{\mathbb{Z}}})$: {I}},
     journal = {Journal of the European Mathematical Society},
     pages = {987--1011},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {2008},
     doi = {10.4171/jems/137},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/137/}
}