@book { BeschwerdemanagementbeiPauschalreiseanbietern,
    title = "Beschwerdemanagement bei Pauschalreiseanbietern",
    author = "Thilo {Baum}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832437459",
    url = "https://m.diplom.de/document/219428"
}