VERY RARE ONLY 9 EXAMPLES - HANS ROSSBACH SIGNED LIMITED EDITION POSTAL COVER NUMBER 6 OF 9 - SIGNED BY GERMAN WORLD WAR ONE PILOT LEUTNANT OTTO BIESENBERGER EKI - BORN 1896 - Signed Postal Cover By Otto Biesenberger. Cover was posted in 1978. Very good condition. COMES WITH  TWO PHOTOS. SLITHER OF PAPER IS FROM ROSSBACHS ORIGINAL LIST.