@inproceedings{grégoire2007on,
title={On the regularity of solutions of optimal transportation problems},
author={Grégoire Loeper},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203353283879713},
booktitle={Acta Mathematica},
volume={202},
number={2},
pages={241-283},
year={2007},
}

Grégoire Loeper. On the regularity of solutions of optimal transportation problems. 2007. Vol. 202. In Acta Mathematica. pp.241-283. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203353283879713.