@Article{ 
  CavMonSem19,
  author = { Cavalletti, Fabio and Mondino, Andrea and Semola, Daniele },
  title = { Quantitative Obata's Theorem },
  journal = { Analysis & PDE },
  year = { 2023 },
  doi = { 10.2140/apde.2023.16.1389 },
  volume = { 16 },
  number = { 6 },
  pages = { 1389–1431 },
  URL = { http://cvgmt.sns.it/paper/4499/ },
  note = { cvgmt preprint}
}