@book { CallCenteralsCRMKomponente,
    title = "Call Center als CRM-Komponente",
    author = "Mahmut {Akar}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832458911",
    url = "https://m.diplom.de/document/221347"
}