@book { RomanoGuardini18851968,
    title = "Romano Guardini (1885-1968)",
    subtitle = "Wegbereiter des 21. Jahrhunderts",
    author = "Magdalena {Börsig-Hover}",
    year = "2009",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1104872"
}