To cite crestr in publications use:

Chevalier M (2021). “crestr An R package to perform probabilistic climate reconstructions using fossil proxies.” Climate of the Past Discussions, 1–35. doi:10.5194/cp-2021-153, https://cp.copernicus.org/preprints/cp-2021-153/.

Corresponding BibTeX entry:

  @Article{,
    title = {{crestr} An R package to perform probabilistic climate
      reconstructions using fossil proxies},
    author = {Manuel Chevalier},
    journal = {Climate of the Past Discussions},
    year = {2021},
    pages = {1--35},
    url = {https://cp.copernicus.org/preprints/cp-2021-153/},
    doi = {10.5194/cp-2021-153},
  }