@book { InnovationimHandel,
    title = "Innovation im Handel",
    subtitle = "Untersucht am Beispiel der Betriebsform Selbstbedienungswarenhaus",
    author = "Maud {Voigtländer}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832484491",
    url = "https://m.diplom.de/document/223243"
}