@book { ReligionundReligionenbeiKarlBarthundJosephRatzinger,
    title = "Religion und Religionen bei Karl Barth und Joseph Ratzinger",
    author = "Michael {Müller}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b14438",
    url = "https://www.peterlang.com/document/1110698"
}