@book { ApostolizittundEinheitderKirche,
    title = "Apostolizität und Einheit der Kirche",
    author = "Aby {Puthukulangara}",
    year = "2019",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b16397",
    url = "https://www.peterlang.com/document/1111150"
}