To cite GNE in publications use:

  Dutang C (????). _GNE: computation of generalized Nash Equilibria_. R
  package version 0.99-7, <https://CRAN.R-project.org/package=GNE>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{GNE}: computation of generalized Nash Equilibria},
    author = {Christophe Dutang},
    note = {R package version 0.99-7},
    url = {https://CRAN.R-project.org/package=GNE},
  }