@book { DerZeisstSprung,
    title = "Der Zeiss(t)-Sprung",
    author = "Kerstin {Koy}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832464691",
    url = "https://m.diplom.de/document/221889"
}