@book { SportaktieneinelohnendeInvestition,
    title = "Sportaktien - eine lohnende Investition?",
    author = "Arnd {Hovemann}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832455347",
    url = "https://m.diplom.de/document/221031"
}