@book { MeinFreundderBaum,
    title = "Mein Freund, der Baum",
    author = "Elke {Fuhrmann-Wönkhaus}",
    year = "2010",
    publisher = "humboldt",
    address = "Hannover, Deutschland",
    url = "https://schluetersche.openpublishing.com/document/403415"
}