To cite package 'GPArotation' in publications use:

Bernaards, Coen A. and Jennrich, Robert I. (2005) Gradient Projection Algorithms and Software for ArbitraryRotation Criteria in Factor Analysis, Educational and Psychological Measurement: 65, 676-696. <http://www.stat.ucla.edu/research/gpa>

Corresponding BibTeX entry:

  @Article{,
    author = {Coen A. Bernaards and Robert I.Jennrich},
    year = {2005},
    title = {Gradient Projection Algorithms and Software for Arbitrary
      Rotation Criteria in Factor Analysis},
    journal = {Educational and Psychological Measurement},
    volume = {65},
    pages = {676--696},
  }