@book { JUNiemcewiczpiewyhistoryczne,
    title = "J. U. Niemcewicz: Śpiewy historyczne",
    subtitle = "Geschichtsauffassung und -darstellung",
    author = "Ilse {Kunert}",
    year = "1968",
    publisher = "Biblion",
    address = ", Germany",
    doi = "10.3726/b12168",
    url = "https://www.peterlang.com/document/1066678"
}