@book { OperationEnduringFreedom,
    title = "Operation Enduring Freedom",
    author = "Stefan {Vedder}",
    year = "2010",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640680795",
    url = "https://www.hausarbeiten.de/document/155838"
}