To cite the psica package in publications use:

Sysoev, O. and Bartoszek, K. and Ekstrom., EC. and Ekholm Selling, K.(2018) PSICA: decision trees for probabilistic subgroup identification with categorical treatments http://arxiv.org/abs/1811.09065

Corresponding BibTeX entry:

  @Article{,
    author = {Oleg Sysoev and Krzysztof Bartoszek and Eva-Charlotta
      Ekstrom and Katarina Ekholm Selling},
    title = {PSICA: decision trees for probabilistic subgroup
      identification with categorical treatments},
    year = {2018},
    journal = {arXiv preprint arXiv:1811.09065},
  }