To cite package ‘evd’ in publications use:

  A. G. Stephenson. evd: Extreme Value Distributions. R News,
  2(2):31-32, June 2002. URL: https://CRAN.R-project.org/doc/Rnews/

A BibTeX entry for LaTeX users is

  @Article{,
    title = {evd: Extreme Value Distributions},
    author = {A. G. Stephenson},
    journal = {R News},
    year = {2002},
    volume = {2},
    number = {2},
    pages = {31-32},
    month = {June},
    url = {https://CRAN.R-project.org/doc/Rnews/},
  }