@book { berregionaleEnergieleitzentralefrdasHandwerk, title = "Überregionale Energieleitzentrale für das Handwerk", author = "Kai {Zitzmann}", year = "1998", publisher = "Diplom.de", address = "Hamburg, Deutschland", doi = "10.3239/9783832407582", url = "https://m.diplom.de/document/216666" }