To cite RGtk2 in publications use:

Michael Lawrence, Duncan Temple Lang (2010). RGtk2: A Graphical User Interface Toolkit for R. Journal of Statistical Software, 37(8), 1-52. URL http://www.jstatsoft.org/v37/i08/.

Corresponding BibTeX entry:

  @Article{,
    title = {{RGtk2}: A Graphical User Interface Toolkit for {R}},
    author = {Michael Lawrence and Duncan {Temple Lang}},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {37},
    number = {8},
    pages = {1--52},
    url = {http://www.jstatsoft.org/v37/i08/},
  }