@book { KommunalesBeteiligungscontrolling,
    title = "Kommunales Beteiligungscontrolling",
    author = "Thomas {Willems}",
    year = "2011",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783842814127",
    url = "https://m.diplom.de/document/228275"
}