To cite package ‘GroupSeq’ in publications use:

Pahl R (2025). GroupSeq: Group Sequential Design Probabilities - With Graphical User Interface. R package version 1.4.4, https://github.com/rpahl/groupseq.

Corresponding BibTeX entry:

  @Manual{,
    title = {GroupSeq: Group Sequential Design Probabilities - With
      Graphical User Interface},
    author = {Roman Pahl},
    year = {2025},
    note = {R package version 1.4.4},
    url = {https://github.com/rpahl/groupseq},
  }