To cite compareGroups in publications use:

Isaac Subirana, Hector Sanz, Joan Vila (2014). Building Bivariate Tables: The compareGroups Package for R. Journal of Statistical Software, 57(12), 1-16. URL http://www.jstatsoft.org/v57/i12/.

Corresponding BibTeX entry:

  @Article{,
    title = {Building Bivariate Tables: The {compareGroups} Package for
      {R}},
    author = {Isaac Subirana and H\'ector Sanz and Joan Vila},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {57},
    number = {12},
    pages = {1--16},
    url = {http://www.jstatsoft.org/v57/i12/},
  }