To cite survsim in publications use:

David Moriña, Albert Navarro (2014). The R Package survsim for the Simulation of Simple and Complex Survival Data. Journal of Statistical Software, 59(2), 1-20. URL http://www.jstatsoft.org/v59/i02/.

Corresponding BibTeX entry:

  @Article{,
    title = {The {R} Package {survsim} for the Simulation of Simple and
      Complex Survival Data},
    author = {David Mori{\~n}a and Albert Navarro},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {59},
    number = {2},
    pages = {1--20},
    url = {http://www.jstatsoft.org/v59/i02/},
  }