@book { HamburgoderHambourg,
    title = "Hamburg oder Hambourg?",
    author = "Helmut {Stubbe da Luz} and Christian F. {Wurm}",
    year = "2021",
    publisher = "Meidenbauer",
    address = ", Germany",
    url = "https://www.peterlang.com/document/1136381"
}