To cite skmeans in publications use:

Kurt Hornik, Ingo Feinerer, Martin Kober, Christian Buchta (2012). Spherical k-Means Clustering. Journal of Statistical Software, 50(10), 1-22. URL http://www.jstatsoft.org/v50/i10/.

Corresponding BibTeX entry:

  @Article{,
    title = {Spherical $k$-Means Clustering},
    author = {Kurt Hornik and Ingo Feinerer and Martin Kober and
      Christian Buchta},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {50},
    number = {10},
    pages = {1--22},
    url = {http://www.jstatsoft.org/v50/i10/},
  }