To cite pssmooth in publications use:

Michal Juraska (2018). pssmooth: Flexible and Efficient Evaluation of Principal Surrogates/Treatment Effect Modifiers. R package version 1.0.1.

Corresponding BibTeX entry:

  @Manual{,
    title = {pssmooth: Flexible and Efficient Evaluation of Principal
      Surrogates/Treatment Effect Modifiers},
    author = {Michal Juraska},
    year = {2018},
    note = {R package version 1.0.1},
  }