To cite kofnGA in publications use:

Mark A. Wolters (2014, in press). A Genetic Algorithm for Selection of Fixed-Size Subsets, With Application to Design Problems Journal of Statistical Software TODO:VOLUME(NUMBER). URL TODO:URL.

Corresponding BibTeX entry:

  @Article{,
    title = {A Genetic Algorithm for Selection of Fixed-Size Subsets,
      With Application to Design Problems},
    author = {Mark A. Wolters},
    journal = {Journal of Statistical Software},
    year = {2015 (in press)},
    volume = {TODO: VOLUME},
    number = {TODO: NUMBER},
    url = {http://cran.r-project.org/web/packages/kofnGA/index.html},
  }