To cite TPmsm in publications use:

Artur Araujo, Luis Meira-Machado, Javier Roca-Pardinas (2014). TPmsm: Estimation of the Transition Probabilities in 3-State Models. Journal of Statistical Software, 62(4), 1-29. URL http://www.jstatsoft.org/v62/i04/.

Corresponding BibTeX entry:

  @Article{,
    title = {{TPmsm}: Estimation of the Transition Probabilities in
      3-State Models},
    author = {Artur Ara{\'u}jo and Lu{\'\i}s Meira-Machado and Javier
      Roca-Pardi{\~n}as},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {62},
    number = {4},
    pages = {1--29},
    url = {http://www.jstatsoft.org/v62/i04/},
  }