@book { AdvancedBookingModel,
    title = "Advanced Booking Model",
    author = "Natascha {Sverak}",
    year = "2010",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836642590",
    url = "https://m.diplom.de/document/227597"
}