@book { TonyundBrunoWerntgenZweiLebenfrdieLuftfahrt,
    title = "Tony und Bruno Werntgen - Zwei Leben für die Luftfahrt",
    author = "Paul {Wirtz} and Ernst {Probst}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640949694",
    url = "https://www.hausarbeiten.de/document/174514"
}