@book { DieVerteidigungdesKugelrundenanderNull,
    title = "«Die Verteidigung des Kugelrunden an der Null»",
    author = "Oliver {Steinhoff}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1105157"
}