@article{BaerWafo2015,
  author    = {Christian B{\"a}r and Roger Tagne Wafo},
  title     = {Initial value problems for wave equations on manifolds},
  journal   = {Mathematical physics, analysis and geometry : an international journal devoted to the theory and applications of analysis and geometry to physics},
  volume    = {18},
  number    = {1},
  doi       = {10.1007/s11040-015-9176-7},
  year      = {2015},
}