@book { OutsourcingvonPersonaldienstleistungen,
    title = "Outsourcing von Personaldienstleistungen",
    author = "Markus {Kaufmann}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832436407",
    url = "https://m.diplom.de/document/219290"
}