To cite package ‘HARplus’ in publications use:

  Puangchit P (2025). _HARplus: Enhanced R Package for 'GEMPACK' .har
  and .sl4 Files_. R package version 1.0.1,
  <https://CRAN.R-project.org/package=HARplus>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {HARplus: Enhanced R Package for 'GEMPACK' .har and .sl4 Files},
    author = {Pattawee Puangchit},
    year = {2025},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=HARplus},
  }