To cite simPH in publications use:

Gandrud C (2015). “simPH: An R Package for Illustrating Estimates from Cox Proportional Hazard Models Including for Interactive and Nonlinear Effects.” Journal of Statistical Software, 65(3), 1–20. https://doi.org/10.18637/jss.v065.i03.

Corresponding BibTeX entry:

  @Article{,
    title = {{simPH}: An {R} Package for Illustrating Estimates from
      Cox Proportional Hazard Models Including for Interactive and
      Nonlinear Effects},
    author = {Christopher Gandrud},
    journal = {Journal of Statistical Software},
    year = {2015},
    volume = {65},
    number = {3},
    pages = {1--20},
    url = {https://doi.org/10.18637/jss.v065.i03},
  }