@inproceedings{mu-tao2011gravitational,
title={Gravitational energy seen by quasilocal observers},
author={Mu-Tao Wang},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160820183722757136343},
booktitle={Classical and Quantum Gravity},
volume={28},
number={11},
pages={114011},
year={2011},
}

Mu-Tao Wang. Gravitational energy seen by quasilocal observers. 2011. Vol. 28. In Classical and Quantum Gravity. pp.114011. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160820183722757136343.