@ARTICLE{Mueller:2008:Twin,
    author = {T. M{\"u}ller and A. King and D. Adis},
    title = {{A trip to the end of the universe and the twin ``paradox''}},
    journal = {Am. J. Phys.},
    year = {2008},
    volume = {76},
    pages = {360--373},
    doi = {10.1119/1.2830528}
}