To cite rpartScore in publications use:

Galimberti G, Soffritti G, Maso MD (2012). “Classification Trees for Ordinal Responses in R: The rpartScore Package.” Journal of Statistical Software, 47(10), 1–25. doi:10.18637/jss.v047.i10.

Corresponding BibTeX entry:

  @Article{,
    title = {Classification Trees for Ordinal Responses in {R}: The
      {rpartScore} Package},
    author = {Giuliano Galimberti and Gabriele Soffritti and Matteo Di
      Maso},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {47},
    number = {10},
    pages = {1--25},
    doi = {10.18637/jss.v047.i10},
  }