To cite cec2005benchmark in publications use:

Yasser Gonzalez-Fernandez and Marta Soto. (2015) cec2005benchmark: Benchmark for the CEC 2005 Special Session on Real-Parameter Optimization. R package version 1.0.4. URL http://CRAN.R-project.org/package=cec2005benchmark.

Corresponding BibTeX entry:

  @Manual{,
    title = {cec2005benchmark: Benchmark for the CEC 2005 Special
      Session on Real-Parameter Optimization},
    author = {Yasser Gonzalez-Fernandez and Marta Soto},
    year = {2015},
    note = {{R} package version 1.0.4},
    url = {http://CRAN.R-project.org/package=cec2005benchmark},
  }