Bidspirit auction | Soviet Union Stamps of 1924-40

Soviet Union Stamps of 1924-40 - 1928, Provisional Government paper money of 1,000rub (so-called Kerenski), in fact issued by RSFSR Bank, used as postcard-invitation to the Leningrad Oblast Philatelic and Paper Money Exhibition, franked by worker 10k brown, sent from Leningrad to Vladivostok, arrival ds is alongside, vertical fold, still VF and very interesting item, Est. $250-$300, Sc. #391