To cite GenSA in publications use:

Y. Xiang, S. Gubian. B. Suomela, J. Hoeng (2013). Generalized Simulated Annealing for Efficient Global Optimization: the GenSA Package for R. The R Journal, Volume 5/1, June 2013. URL http://journal.r-project.org/.

Corresponding BibTeX entry:

  @Article{,
    title = {Generalized Simulated Annealing for Efficient Global
      Optimization: the {GenSA} Package for {R}.},
    author = {{Yang Xiang} and Sylvain Gubian and Brian Suomela and
      Julia Hoeng},
    journal = {The R Journal Volume 5/1, June 2013},
    year = {2013},
    url = {http://journal.r-project.org/},
  }