@article{JMLR:v17:15-381,
  author  = {Yohann De Castro and Élisabeth Gassiat and Claire Lacour},
  title   = {Minimax Adaptive Estimation of Nonparametric Hidden Markov Models},
  journal = {Journal of Machine Learning Research},
  year    = {2016},
  volume  = {17},
  number  = {111},
  pages   = {1--43},
  url     = {http://jmlr.org/papers/v17/15-381.html}
}