To cite RStan in publications use:

  Stan Development Team (2024). RStan: the R interface to Stan. R
  package version 2.32.6. https://mc-stan.org/.

A BibTeX entry for LaTeX users is

  @Misc{,
    title = {{RStan}: the {R} interface to {Stan}},
    author = {{Stan Development Team}},
    note = {R package version 2.32.6},
    year = {2024},
    url = {https://mc-stan.org/},
  }