@inproceedings{simon2007classification,
  title={Classification of manifolds with weakly 1/4-pinched curvatures},
  author={Simon Brendle, and Richard M. Schoen},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203351354809698},
  booktitle={Acta Mathematica},
  volume={200},
  number={1},
  pages={1-13},
  year={2007},
}
             
            
                
Simon Brendle, and Richard M. Schoen. Classification of manifolds with weakly 1/4-pinched curvatures. 2007. Vol. 200. In Acta Mathematica. pp.1-13. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203351354809698.