1930 (May 13), flown cover from Sofia to Hamburg, franked by ten stamps, delivered by two connected Pioneer Flights Sofia - Nuremberg/Fürth and Nuremberg/Fürth - Hamburg, two appropriate air post markings on front, backstamped, punch at right, still F/VF and scarce, Est. $200-$300 (Image)

1979, Centenary of the Bulgarian Postage Stamp, 5L multicolored, souvenir sheet numbered at bottom in block containing four sheets, numbers 02084, 05334, 08584 and 11834, housed in a souvenir folder, full OG, NH, VF, Mi Block 91, €250, Est. $80-$100 (Image)

1979, Centenary of the Bulgarian Postage Stamp, 5L multicolored, souvenir sheet numbered at bottom in block of four, three blocks, each one housed in a souvenir folder, full OG, NH, VF, Mi Block 91, €750, Est. $200-$300 (Image)