@ARTICLE{Grave:2009:Goe,
    author = {F. Grave and M. Buser and T. M{\"u}ller and G. Wunner and W. P. Schleich},
    title = {{The G\"odel universe: Exact geometrical optics and analytical investigations on motion}},
    journal = {Phys. Rev. D},
    year = {2009},
    volume = {80},
    pages = {103002},
    doi = {10.1103/PhysRevD.80.103002}
}