@book { DasSponsoringvonSportveranstaltungen,
    title = "Das Sponsoring von Sportveranstaltungen",
    author = "Frank {Häußler}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832402860",
    url = "https://m.diplom.de/document/216272"
}