To cite package ‘futility’ in publications use:

Zhuang Y, Juraska M (2026). futility: Interim Analysis of Operational Futility in Randomized Trials with Time-to-Event Endpoints and Fixed Follow-Up. R package version 0.5, https://github.com/mjuraska/futility.

Corresponding BibTeX entry:

  @Manual{,
    title = {futility: Interim Analysis of Operational Futility in
      Randomized Trials with Time-to-Event Endpoints and Fixed
      Follow-Up},
    author = {Yingying Zhuang and Michal Juraska},
    year = {2026},
    note = {R package version 0.5},
    url = {https://github.com/mjuraska/futility},
  }