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

1926, King Ferdinand 60th Birthday issue, 94 plate or trial color perforated (6) or imperforated proofs of 25b and 10L on glossy paper, thin cards or gummed stamp paper, including 15 se-tenant pairs, two strips of four and five blocks of four, all are arranged on six pages from a Collection, mainly VF and very rare group, Est. $1,600-$2,000