@book { AufFeindfahrtmitSMU5,
    title = "Auf Feindfahrt mit SM U 5",
    author = "Georg Ritter {von Trapp} and EK-2 {Militär}",
    year = "2022",
    publisher = "EK-2 Publishing",
    address = ", Deutschland",
    url = "https://tolino.openpublishing.com/document/1315275"
}