@BOOK{CDDG_2022,
  author =       {Xianfeng Gu and Emil Saucan},
  title =        {Classical and Discrete Differential Geometry},
  publisher =    {CRC Press and Posts \& Telcom Press},
  year =         {2022},
  isbn =         {978-1-032-39017-8},
  doi  = {10.1201/9781003350576}
}