"ΑΘΗΝΑΙ*13.IX.31" first flight cover to "BERLIN*15.9.31" via (THESSALONIKI) by EEES/AP (flight extended at BELGRADE) with air-cachet type 6 in violet, with commemorative canc. "MIT LUFTPOST BEFORDERT*LUFTPOSTAMP*BERLIN C2" in red. 30 covers flown. (Hellas FF188).