1943 STAMP EXHIBITION: Registered cover and registered card, both delivered from the Special Exhibition post office which used the 6 and 15 Pfg. stamps with marginal imprint "Briefmarkenschau Riga, 1.-2. Mai 43", the letter franked with Hitler 6 Pfg. three singles and 12 Pfg. as horizontal pair, the card franked with Hitler 6 Pfg. and additional franking, both addressed to Riga, the only known entires with this marginal imprint, in addition both receipts, very fine
Reference: "Lettland vor dem und als Teil vom Generalkommissariat OSTLAND", page 60-61, Harry von Hofmann (2001)
