Bulgarian Posts Issue New Stamp Bulgarian Posts Ltd issued on Wednesday a souvenir sheet, a special stamped envelope and a special cachet to mark the 10th anniversary of the establishment of the Atlantic Club of Bulgaria. The circulation of the sheet is 30,000 and of the envelope 2,100. The stamp and the envelope bear the NATO logo and the anniversary. The size of the sheet is 28.5 mm by 33 mm. It is printed on white paper protected by a UV-thread. The Museum of Posts has staged an exhibition of 41 stamps on NATO issued in Bulgaria and other countries.