@book { DiegeistlichenGrundlagenderIkone,
    title = "Die geistlichen Grundlagen der Ikone",
    author = "Wolfgang {Kasack}",
    year = "1989",
    publisher = "Biblion",
    address = ", Germany",
    doi = "10.3726/b12841",
    url = "https://www.peterlang.com/document/1067211"
}