Bulgaria 1997  Bulgarian Space Research 25th Anniversary  1 value miniature sheet featuring Radiometric System, Radio Equipment, Map   -  in superb u/m (mnh) condition - excellent country, radio, science, research, space thematics. If you cannot see the topic/thematic you are searching for in my shop, please do not hesitate to request that I send up a selection of items to ebay which suit you better as I have huge stocks!