@inproceedings{alexander2003subgroup,
title={Subgroup growth of lattices in semisimple Lie groups},
author={Alexander Lubotzky, and Nikolay Nikolov},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203345339309655},
booktitle={Acta Mathematica},
volume={193},
number={1},
pages={105-139},
year={2003},
}
Alexander Lubotzky, and Nikolay Nikolov. Subgroup growth of lattices in semisimple Lie groups. 2003. Vol. 193. In Acta Mathematica. pp.105-139. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203345339309655.