To cite clues in publications use:

Fang Chang, Weiliang Qiu, Ruben H. Zamar, Ross Lazarus, Xiaogang Wang (2010). clues: An R Package for Nonparametric Clustering Based on Local Shrinking. Journal of Statistical Software, 33(4), 1-16. URL http://www.jstatsoft.org/v33/i04/.

Corresponding BibTeX entry:

  @Article{,
    title = {{clues}: An {R} Package for Nonparametric Clustering Based
      on Local Shrinking},
    author = {Fang Chang and Weiliang Qiu and Ruben H. Zamar and Ross
      Lazarus and Xiaogang Wang},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {33},
    number = {4},
    pages = {1--16},
    url = {http://www.jstatsoft.org/v33/i04/},
  }