by Karl Wilhelm Friedrich Johannes Valentiner

1899

by Wilhelm Valentiner

1899

by Wilhelm Hausenstein

1926

by Frans Hals, Wilhelm Reinhold Valentiner

1921

by Kaiser Wilhelm Institut für Kohlenforschung, Mülheim-am-Ruhr

1930

by Mülheim an der Ruhr (Germany). Kaiser-Wilhelm-Institut für Kohlenforschung

1930

by Wilhelm Reinhold Valentiner

1923

by August Wilhelm Ambros

1882