Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Bulgaria - Zeppelin Flight - 1933 (May 6-9), 1st SAF registered cover to Brazil, franked by nine air post values, cancelled by Sofia ''3.V.933'' ds, red Berlin-Friedrichshafen connection and blue flight cachet, Pernambuco ''9.V.33'' receiver, VF and rare, Sieger #202, C.v. €850, Est. $400-$500, Scott #C5/11