@book { PharmareferentMarketinginstrumentmitZukunft,
    title = "Pharmareferent - Marketinginstrument mit Zukunft?",
    author = "Michael {Müller}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832485689",
    url = "https://m.diplom.de/document/223766"
}