@book { KonstruktivistischeUnterrichtsforschung,
    title = "Konstruktivistische Unterrichtsforschung",
    author = "Hermann {Krüssel}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1081171"
}