To cite the prettyGraphs package in publications use:

Beaton, D., Fatt, C. R. C., & Abdi, H. (2014). An ExPosition of multivariate analysis with the singular value decomposition in R. Computational Statistics & Data Analysis, 72(0), 176--189.

Corresponding BibTeX entry:

  @Article{,
    title = {An {ExPosition} of multivariate analysis with the singular
      value decomposition in {R}.},
    author = {Derek Beaton and Cherise R. Chin Fatt and Herve Abdi},
    journal = {Computational Statistics & Data Analysis },
    volume = {72},
    number = {0},
    pages = {176 - 189},
    year = {2014},
    issn = {0167-9473},
    doi = {10.1016/j.csda.2013.11.006},
    url =
      {http://www.sciencedirect.com/science/article/pii/S0167947313004441},
  }