@book { StrategischesOutsourcing,
    title = "Strategisches Outsourcing",
    author = "Dirk {Jacobsen}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832479671",
    url = "https://m.diplom.de/document/222995"
}