To cite package ‘gputools’ in publications use:

  Buckner J, Wilson J, Seligman M, Athey B, Watson S, Meng F (2010).
  “The gputools package enables GPU computing in R.” _Bioinformatics_,
  *26*(1), 134-135. doi:10.1093/bioinformatics/btp608
  <https://doi.org/10.1093/bioinformatics/btp608>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {The gputools package enables GPU computing in R},
    author = {Joshua Buckner and Justin Wilson and Mark Seligman and Brian Athey and Stanley Watson and Fan Meng},
    journal = {Bioinformatics},
    year = {2010},
    volume = {26},
    number = {1},
    pages = {134--135},
    doi = {10.1093/bioinformatics/btp608},
  }