@book { HeideggerunddasMittelalter,
    title = "Heidegger und das Mittelalter",
    subtitle = "Wiener Tagungen zur Phänomenologie 1997",
    author = "Helmuth {Vetter}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1087827"
}