To cite package markovchain in publications use:

Giorgio Alfredo Spedicato. markovchain: an R package to easily handle discrete Markov chains

Corresponding BibTeX entry:

  @Manual{,
    title = {markovchain: an R package to easily handle discrete Markov
      chains},
    author = {Giorgio Alfredo Spedicato},
    month = {02},
    year = {2014},
    note = {R package version 0.0.8},
  }