@article{Uschmajew2010,
  author    = {Andr{\´e} Uschmajew},
  title     = {Well-posedness of convex maximization problems on Stiefel manifolds and orthogonal tensor product approximations},
  journal   = {Numerische Mathematik},
  volume    = {115},
  number    = {2},
  pages     = {309 -- 331},
  doi       = {10.1007/s00211-009-0276-9},
  year      = {2010},
}