To cite tuple in publications use:

Lazaridis, E. (2014). tuple: Find every match, or orphan, duplicate, triplicate, or other replicated values (Version 0.4-02). Available from http://statistics.lazaridis.eu

Corresponding BibTeX entry:

  @Manual{,
    title = {tuple: Find every match, or orphan, duplicate, triplicate,
      or other replicated values},
    author = {Emmanuel Lazaridis},
    year = {2014},
    note = {(Version 0.4-02)},
    url = {http://statistics.lazaridis.eu},
  }