@book { VomWertderKooperation,
    title = "Vom Wert der Kooperation",
    author = " {Arbeitskreis Kooperative Pädagogik}",
    year = "2002",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1092240"
}