@book { WiderstandinderWehrmachtvordem20Juli,
    title = "Widerstand in der Wehrmacht vor dem 20. Juli",
    author = "Michael {Preis}",
    year = "2006",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638507189",
    url = "https://www.hausarbeiten.de/document/55878"
}