@book { KontinuittgegenWiderwrtigkeit,
    title = "Kontinuität gegen Widerwärtigkeit",
    author = "Helmut {Schaller} and Rumjana {Zlatanova}",
    year = "2013",
    publisher = "Biblion",
    address = ", Germany",
    doi = "10.3726/b12123",
    url = "https://www.peterlang.com/document/1056395"
}