@inproceedings{wilfrid1996the,
title={The geometry of optimal transportation},
author={Wilfrid Gangbo, and Robert J. McCann},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203327775797537},
booktitle={Acta Mathematica},
volume={177},
number={2},
pages={113-161},
year={1996},
}