@Article{prd09-grave,
  author = {Grave, F. and Buser, M. and Müller, T. and  Wunner, G. and Schleich, W.},
  title  = {{The Gödel universe: Exact geometrical optics and analytical investigations on motion}},
  year   = {2009},
  pages  = {103002},
  journal = {{Physical Review D}},
  volume = {80}
}