To cite FrF2 in publications use:

Gr"omping U (2014). “R Package FrF2 for Creating and Analyzing Fractional Factorial 2-Level Designs.” Journal of Statistical Software, 56(1), 1–56. http://www.jstatsoft.org/v56/i01/.

Corresponding BibTeX entry:

  @Article{,
    title = {{R} Package {FrF2} for Creating and Analyzing Fractional
      Factorial 2-Level Designs},
    author = {Ulrike Gr"omping},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {56},
    number = {1},
    pages = {1--56},
    url = {http://www.jstatsoft.org/v56/i01/},
  }