@inproceedings{huai-dong2013on, title={ON Bach-flat Gradient Shrinking Ricci Solitons}, author={Huai-Dong Cao, and Qiang Chen}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170313110051106859664}, booktitle={Duke Math. J. }, volume={162}, number={6}, pages={1149–1169}, year={2013}, }