@inproceedings{hui-chun2010ricci,
  title={RICCI CURVATURE ON ALEXANDROV SPACES AND RIGIDITY THEOREM},
  author={Hui-Chun Zhang, and Xi-Ping Zhu},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160910123214098274758},
  booktitle={Comm. Anal. Geom.},
  volume={18},
  number={3},
  pages={503–553},
  year={2010},
}
             
            
                
Hui-Chun Zhang, and Xi-Ping Zhu. RICCI CURVATURE ON ALEXANDROV SPACES AND RIGIDITY THEOREM. 2010. Vol. 18. In Comm. Anal. Geom.. pp.503–553. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160910123214098274758.