To cite package 'rioja' in publications use:

Juggins S (2020). rioja: Analysis of Quaternary Science Data. R package version 0.9-26, https://cran.r-project.org/package=rioja.

Corresponding BibTeX entry:

  @Manual{,
    title = {rioja: Analysis of Quaternary Science Data},
    author = {Steve Juggins},
    year = {2020},
    note = {R package version 0.9-26},
    url = {https://cran.r-project.org/package=rioja},
  }