Lot 2921
Treaty post, Flight to Vienna of the Graf Zeppelin (Sieger 116A), Furstensteig 5 rappen green, Airplane 15 rappen black brown, 20 rappen black grey in block of 4 with corner margin and 45 rappen black olive in block of 4 with corner margin on cover from Schaan 9-7-1931 via Friedrichshafen to Liesing (Austria), very fine