To cite PtProcess in publications use:

David Harte (2010). PtProcess: An R Package for Modelling Marked Point Processes Indexed by Time. Journal of Statistical Software, 35(8), 1-32. URL http://www.jstatsoft.org/v35/i08/.

Corresponding BibTeX entry:

  @Article{,
    title = {{PtProcess}: An {R} Package for Modelling Marked Point
      Processes Indexed by Time},
    author = {David Harte},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {35},
    number = {8},
    pages = {1--32},
    url = {http://www.jstatsoft.org/v35/i08/},
  }