@article{gao03discrete
    ,author = "J. Gao and L. Guibas and J. Hershberger and L.  Zhang
            and A. Zhu"
    ,title = "Discrete Mobile Centers"
    ,journal = "Discrete and Computational Geometry"
    ,year = "2003"
    ,volume = "30"
    ,number = "1"
    ,pages = "45--65"
}