To cite mhsmm in publications use:

Jared O'Connell, Soren Hojsgaard (2011). Hidden Semi Markov Models for Multiple Observation Sequences: The mhsmm Package for R. Journal of Statistical Software, 39(4), 1-22. URL http://www.jstatsoft.org/v39/i04/.

Corresponding BibTeX entry:

  @Article{,
    title = {Hidden Semi Markov Models for Multiple Observation
      Sequences: The {mhsmm} Package for {R}},
    author = {Jared O'Connell and Søren Højsgaard},
    journal = {Journal of Statistical Software},
    year = {2011},
    volume = {39},
    number = {4},
    pages = {1--22},
    url = {http://www.jstatsoft.org/v39/i04/},
  }