@book { RenAhlbergGesammelteWerkeIX,
    title = "René Ahlberg- Gesammelte Werke IX",
    author = "Hartmut {Salzwedel} and Ingeborg {Siggelkow} and Brigitte {Ahlberg}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1100786"
}