@Article{ 
  Li12a,
  author = { Li, Yi },
  title = { On an extension of the $H^{k}$  mean curvature flow },
  journal = { Science China Mathematics },
  year = { 2012 },
  doi = { 10.1007/s11425-011-4289-3 },
  volume = { 55 },
  number = { 1 },
  pages = { 99-118 },
  URL = { http://cvgmt.sns.it/paper/3287/ },
  note = { cvgmt preprint}
}