To cite package 'Ckmeans.1d.dp' in publications use:

Wang, H. and Song, M. (2011) Ckmeans.1d.dp: optimal k-means clustering in one dimension by dynamic programming. The R Journal 3(2), 29-33. Retrieved from URL http://journal.r-project.org/archive/2011-2/RJournal_2011-2_Wang+Song.pdf

Corresponding BibTeX entry:

  @Article{Wang2011Ckmeans,
    title = {Ckmeans.1d.dp: Optimal $k$-means Clustering in One
      Dimension by Dynamic Programming},
    journal = {The R Journal},
    volume = {3},
    number = {2},
    pages = {29--33},
    year = {2011},
    author = {H. Wang and M. Song},
    url =
      {http://journal.r-project.org/archive/2011-2/RJournal_2011-2_Wang+Song.pdf},
  }