@article{JMLR:v20:17-687,
  author  = {Kevin L. Keys and Hua Zhou and Kenneth Lange},
  title   = {Proximal Distance Algorithms: Theory and Practice},
  journal = {Journal of Machine Learning Research},
  year    = {2019},
  volume  = {20},
  number  = {66},
  pages   = {1--38},
  url     = {http://jmlr.org/papers/v20/17-687.html}
}