WIA GC 1930/1503
KBW to Karl W. Hiersemann 27/03/1930
WIA GC 1930/1504
Karl W. Hiersemann to Bing, Gertrud 29/03/1930
WIA GC 1931/1255
Karl W. Hiersemann to KBW 16/01/1931
WIA GC 1931/1256
KBW to Karl W. Hiersemann 23/05/1931
WIA GC 1931/1257
Karl W. Hiersemann to KBW 27/05/1931