@book { VersteckteAussichten,
    title = "Versteckte Aussichten",
    author = "Christoph {Duckart}",
    year = "2010",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783842805637",
    url = "https://m.diplom.de/document/228085"
}