@book { DerStdteundKulturtourismusinMadrid,
    title = "Der Städte- und Kulturtourismus in Madrid",
    author = "Janet {Meier}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832478322",
    url = "https://m.diplom.de/document/223090"
}