@book { ArbeiteninderGrauzone,
    title = "Arbeiten in der Grauzone",
    author = "Dietrich {Henckel} and Guido {Spars} and Florian {Wukovitsch}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1105002"
}