To cite nullabor in publications use this:

Buja A, Cook D, Hofmann H, Lawrence M, Lee E, Swayne DF, Wickham H (2009). “Statistical Inference for Exploratory Data Analysis and Model Diagnostics.” Royal Society Philosophical Transactions A, 367(1906), 4361–4383. http://rsta.royalsocietypublishing.org/content/367/1906/4361.article-info.

Corresponding BibTeX entry:

  @Article{,
    title = {Statistical Inference for Exploratory Data Analysis and
      Model Diagnostics},
    author = {Andreas Buja and Dianne Cook and Heike Hofmann and
      Michael Lawrence and Eun-kyung Lee and Deborah F. Swayne and
      Hadley Wickham},
    journal = {Royal Society Philosophical Transactions A},
    year = {2009},
    volume = {367},
    number = {1906},
    pages = {4361--4383},
    url =
      {http://rsta.royalsocietypublishing.org/content/367/1906/4361.article-info},
  }