@book { DieRentensystemeinPolenundUngarn,
    title = "Die Rentensysteme in Polen und Ungarn",
    author = "Angelika {Bucerius}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1099114"
}