To cite package ‘H2x2Factorial’ in publications use:

Tian Z, Esserman D, Tong G, Li F (2022). H2x2Factorial: Sample Size Calculation in Hierarchical 2x2 Factorial Trials. R package version 2.0.0, https://github.com/billytian/h2x2factorial.

Corresponding BibTeX entry:

  @Manual{,
    title = {H2x2Factorial: Sample Size Calculation in Hierarchical 2x2
      Factorial Trials},
    author = {Zizhong Tian and Denise Esserman and Guangyu Tong and Fan
      Li},
    year = {2022},
    note = {R package version 2.0.0},
    url = {https://github.com/billytian/h2x2factorial},
  }