@Misc{ 
  MarRimVer20,
  author = { Honda, Shouhei and Mari, Luciano and Rimoldi, Michele and Veronelli, Giona },
  title = { Density and non-density of $C^\infty_c \hookrightarrow W^{k,p}$ on  complete manifolds with curvature bounds },
  journal = { Nonlinear Anal. },
  year = { 2021 },
  volume = { 211 },
  pages = { 26 },
  URL = { http://cvgmt.sns.it/paper/4918/ },
  note = { cvgmt preprint}
}