To cite package ‘submax’ in publications use:

  Rosenbaum PR (2025). _submax: Effect Modification in Observational
  Studies Using the Submax Method_. R package version 1.1.5,
  <https://CRAN.R-project.org/package=submax>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {submax: Effect Modification in Observational Studies Using the Submax
Method},
    author = {Paul R. Rosenbaum},
    year = {2025},
    note = {R package version 1.1.5},
    url = {https://CRAN.R-project.org/package=submax},
  }