@book { EinfhrungeinerDienstleistungsmarke,
    title = "Einführung einer Dienstleistungsmarke",
    author = "Elias {Glauche}",
    year = "1998",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832411022",
    url = "https://m.diplom.de/document/216992"
}