To cite POT in publications use:

  Mathieu Ribatet and Christophe Dutang (). POT: Generalized Pareto
  Distribution and Peaks Over Threshold. R package version 1.1-10.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{POT}: Generalized Pareto Distribution and Peaks Over Threshold},
    author = {Mathieu Ribatet and Christophe Dutang},
    note = {R package version 1.1-10},
    url = {https://CRAN.R-project.org/package=POT},
  }

Please cite both the package and R when using them for data analysis.
See also ‘citation()’ for citing R.