To cite package ‘eselect’ in publications use:

Bofill Roig M (2023). eselect: Adaptive Clinical Trial Designs with Endpoint Selection and Sample Size Reassessment. R package version 1.1, https://CRAN.R-project.org/package=eselect.

Corresponding BibTeX entry:

  @Manual{,
    title = {eselect: Adaptive Clinical Trial Designs with Endpoint
      Selection and Sample Size Reassessment},
    author = {Marta {Bofill Roig}},
    year = {2023},
    note = {R package version 1.1},
    url = {https://CRAN.R-project.org/package=eselect},
  }