To cite tclust in publications use:

Heinrich Fritz, Luis A. Garcia-Escudero, Agustin Mayo-Iscar (2012). tclust: An R Package for a Trimming Approach to Cluster Analysis. Journal of Statistical Software, 47(12), 1-26. URL http://www.jstatsoft.org/v47/i12/.

Corresponding BibTeX entry:

  @Article{,
    title = {{tclust}: An {R} Package for a Trimming Approach to
      Cluster Analysis},
    author = {Heinrich Fritz and Luis A. Garc\'{\i}a-Escudero and
      Agust\'{\i}n Mayo-Iscar},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {47},
    number = {12},
    pages = {1--26},
    url = {http://www.jstatsoft.org/v47/i12/},
  }