@book { DASKLEINELEOSAMMELSURIUM, title = "DAS KLEINE LEO-SAMMELSURIUM", subtitle = "mit Hörbuch und Lieder-CD", author = "Ulrich Michael {Heissig}", year = "2021", publisher = "Omnino Verlag", address = "Berlin, Deutschland", url = "https://shop.omnino-verlag.de/document/1038031" }