To cite package ‘ggrcs’ in publications use:

  LIU Q (2025). _ggrcs: Draw Histograms and Restricted Cubic Splines
  (RCS)_. R package version 0.4.3,
  <https://CRAN.R-project.org/package=ggrcs>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ggrcs: Draw Histograms and Restricted Cubic Splines (RCS)},
    author = {Qiang LIU},
    year = {2025},
    note = {R package version 0.4.3},
    url = {https://CRAN.R-project.org/package=ggrcs},
  }