@book { NachHeidegger,
    title = "Nach Heidegger",
    subtitle = "Einblicke – Ausblicke",
    author = "Helmuth {Vetter}",
    year = "2003",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1095108"
}