@book{ 0-1145605710, title = {Die Porträtdarstellungen Karls des Großen}, author = {Clemen, Paul}, address = {Aachen}, publisher = {Cremer}, year = {1890}, language = {German}, note = {Auch in: Zeitschrift des Aachener Geschichtsvereins ; 11, 12}, url = {https://katalog.skd.museum/Record/0-1145605710} }