@book { SponsoringdesGolfsportsinDeutschland,
    title = "Sponsoring des Golfsports in Deutschland",
    author = "Daniel {Gronen}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832478308",
    url = "https://m.diplom.de/document/223088"
}