@book { EinelaunischeFruchtnamensHoffnung,
    title = "Eine launische Frucht namens Hoffnung",
    author = "Gret {Weyden}",
    year = "2013",
    publisher = "hey! publishing",
    address = "München, Deutschland",
    doi = "10.3239/9783942822756",
    url = "https://www.heypublishing.com/document/213707"
}