@book { AHistoryofMedievalChristianity,
    title = "A History of Medieval Christianity",
    author = "Jeffrey Burton {Russell} and Douglas W. {Lumsden}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "New York, United States of America",
    url = "https://www.peterlang.com/document/1103908"
}