@book { ErwerbeigenerAktien,
    title = "Erwerb eigener Aktien",
    subtitle = "Probleme, Verfahren und Auswirkungen",
    author = "Ralf {Koschmieder}",
    year = "2000",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832423339",
    url = "https://m.diplom.de/document/218147"
}