@book { DieKundenkarteimdeutschenEinzelhandel,
    title = "Die Kundenkarte im deutschen Einzelhandel",
    author = "Anne {Bury}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832445218",
    url = "https://m.diplom.de/document/220122"
}