To cite package ‘CFO’ in publications use:

  Fang J, Wang W, Zhang N, Yin G (2024). _CFO: CFO-Type Designs in
  Phase I/II Clinical Trials_. R package version 2.0.0,
  <https://CRAN.R-project.org/package=CFO>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {CFO: CFO-Type Designs in Phase I/II Clinical Trials},
    author = {Jialu Fang and Wenliang Wang and Ninghao Zhang and Guosheng Yin},
    year = {2024},
    note = {R package version 2.0.0},
    url = {https://CRAN.R-project.org/package=CFO},
  }