To cite tuneR in publications use:

  Uwe Ligges, Sebastian Krey, Olaf Mersmann, and Sarah Schnackenberg
  (2023). tuneR: Analysis of Music and Speech. URL:
  https://CRAN.R-project.org/package=tuneR

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{tuneR}: Analysis of Music and Speech},
    author = {Uwe Ligges and Sebastian Krey and Olaf Mersmann and Sarah Schnackenberg},
    year = {2023},
    url = {https://CRAN.R-project.org/package=tuneR},
  }