Auction #93 Worldwide Air Post stamps and postal history, Zeppelin Flight items, philatelic rarities of the World

1922, Volga Famine Relief issue, violet overprint (25mm) ''Bakinskago G.P.T.O. No.1'' on 500r and 1000r, set of two in horizontal pairs, neat Baku cancellation, minor foxing, still F/VF and extremely rare in used condition, Standard Cat. #11 II-12 II, each used stamp priced with ''-'', first pair with expert's sign on reverse, Est. $700-$800