@BOOK{VP_2007,
  author =       {Feng Luo and Xianfeng Gu and Junfei Dai},
  title =        {Variational Principles for Discrete Surfaces},
  publisher =    {International Press and Higher Education Press},
  year =         {2007},
  volume =       {4},
  series =       {Advanced Lectures in Mathematics},
  isbn =         {978-1-57146-172-8},
  source =
  {https://www.amazon.com/Variational-Principles-Discrete-Surfaces-Mathematics/dp/1571461728},
}