@article{JMLR:v22:20-1194,
  author  = {Yikun Zhang and Yen-Chi Chen},
  title   = {Kernel Smoothing, Mean Shift, and Their Learning Theory with Directional Data},
  journal = {Journal of Machine Learning Research},
  year    = {2021},
  volume  = {22},
  number  = {154},
  pages   = {1--92},
  url     = {http://jmlr.org/papers/v22/20-1194.html}
}