To cite package ‘twoCoprimary’ in publications use:

  Homma G (2026). _twoCoprimary: Sample Size and Power Calculation for
  Two Co-Primary Endpoints_. R package version 1.0.0,
  <https://github.com/gosukehommaex/twocoprimary>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {twoCoprimary: Sample Size and Power Calculation for Two Co-Primary Endpoints},
    author = {Gosuke Homma},
    year = {2026},
    note = {R package version 1.0.0},
    url = {https://github.com/gosukehommaex/twocoprimary},
  }