@Misc{ 
  ShaLiuZho20,
  author = { Liu, Qing and Shanmugalingam, Nageswari and Zhou, Xiaodan },
  title = { Equivalence of solutions of eikonal equation in metric spaces },
  journal = {  },
  year = { 2020 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4684/ },
  note = { cvgmt preprint}
}