To cite the 'circular' package in publications use:

Agostinelli, C. and Lund, U. (2023). R package 'circular': Circular Statistics (version 0.5-0). URL https://CRAN.R-project.org/package=circular

Corresponding BibTeX entry:

  @Manual{,
    title = {{R} package \texttt{circular}: Circular Statistics
      (version 0.5-0)},
    author = {Claudio Agostinelli and Ulric Lund},
    year = {2023},
    url = {https://CRAN.R-project.org/package=circular},
  }