@ARTICLE{Mueller:2009:M4D,
    author = {T. M{\"u}ller and F. Grave},
    title = {{Motion4D - A library for lightrays and timelike worldlines in the theory of relativity}},
    journal = {Computer Physics Communications},
    year = {2009},
    volume = {180},
    pages = {2355--2360},
    doi = {10.1016/j.cpc.2009.07.014}
}