@INCOLLECTION{Metric_Gu_2011,
  author =       {Xianfeng Gu and Wei Zeng and Jian
  Sun and Ren Guo and Feng Luo},
  title =        {Metric and Heat Kernel},
  booktitle =    {Manifold Learning Theory and
  Applications},
  publisher =    {CRC Press},
  year =         {2011},
  editor =       {Yunqian Ma and Yun Fu},
  chapter =      {7},
}