To cite cec2013 in publications use:

Mauricio Zambrano-Bigiarini and Yasser Gonzalez-Fernandez. (2015) cec2013: Benchmark Functions for the Special Session and Competition on Real-Parameter Single Objective Optimization at CEC-2013R package version 0.1-5. URL http://CRAN.R-project.org/package=cec2013.

Corresponding BibTeX entry:

  @Manual{,
    title = {cec2013: Benchmark Functions for the Special Session and
      Competition on Real-Parameter Single Objective Optimization at
      CEC-2013},
    author = {Mauricio Zambrano-Bigiarini and Yasser
      Gonzalez-Fernandez},
    year = {2015},
    note = {{R} package version 0.1-5},
    url = {http://CRAN.R-project.org/package=cec2013},
  }