@book { DieKluftzwischenKampfundKontemplation,
    title = "Die Kluft zwischen Kampf und Kontemplation",
    author = "Berthold {Volberg}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1088196"
}