@book { MobileInformationsdiensteimZooaufBasisvonLocationBasedServices,
    title = "Mobile Informationsdienste im Zoo auf Basis von Location Based Services",
    author = "Markus {Ebeling}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832478483",
    url = "https://m.diplom.de/document/223105"
}