@inproceedings{marina1989on,
title={On measure rigidity of unipotent subgroups of semisimple groups},
author={Marina Ratner},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203315091606450},
booktitle={Acta Mathematica},
volume={165},
number={1},
pages={229-309},
year={1989},
}