@book { MobileLocationBasedServices,
    title = "Mobile Location Based Services",
    author = "Ralf {Ganßleben}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832465575",
    url = "https://m.diplom.de/document/221952"
}