@inproceedings{sorin2012unique,
title={Unique Cartan decomposition for II_{1}factors arising from arbitrary actions of free groups},
author={Sorin Popa, and Stefaan Vaes},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203402567310786},
booktitle={Acta Mathematica},
volume={212},
number={1},
pages={141-198},
year={2012},
}

Sorin Popa, and Stefaan Vaes. Unique Cartan decomposition for II_{1}factors arising from arbitrary actions of free groups. 2012. Vol. 212. In Acta Mathematica. pp.141-198. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203402567310786.