@book { IncomingTourismusinDeutschland,
    title = "Incoming-Tourismus in Deutschland",
    author = "Nadine {Dietrich}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832443412",
    url = "https://m.diplom.de/document/219953"
}