@inproceedings{wen-ling2006positivity,
title={Positivity of the Bondi mass in Bondi's radiating spacetimes},
author={Wen-ling Huang, Shing-Tung Yau, and Xiao Zhang},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224204522448816188},
booktitle={arXiv preprint math/0604155},
year={2006},
}
Wen-ling Huang, Shing-Tung Yau, and Xiao Zhang. Positivity of the Bondi mass in Bondi's radiating spacetimes. 2006. In arXiv preprint math/0604155. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224204522448816188.