@book { MichelangeloStudienIV,
    title = "Michelangelo Studien IV",
    subtitle = "Die 'Michelangelo'-Zeichnungen Benvenuto Cellinis",
    author = "Alexander {Perrig}",
    year = "1978",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1070168"
}