To cite package markovchain in publications use:

Giorgio Alfredo Spedicato markovchain: discrete time Markov chains made easy

Corresponding BibTeX entry:

  @Manual{,
    title = {markovchain: Easy Handling of Discrete Time Markov
      Chains},
    author = {Giorgio Alfredo Spedicato},
    month = {03},
    year = {2017},
    note = {R package version 0.6.8.1},
  }