@book { Zeitbetrachtungen,
    title = "Zeitbetrachtungen",
    author = "Martina {Kattein} and Matthias {Vonken}",
    year = "2013",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-03023-5",
    url = "https://www.peterlang.com/document/1047641"
}