The World Association for the Development of Philately (WADP) and the Universal Postal Union (UPU) jointly conceived and developed the WADP Numbering System - WNS, which was launched on 1 January 2002.

BG006.11

Country / Post Bulgaria
Date of Issue 12 April 2011
Primary theme Astronomy & Space (Astronauts & Cosmonauts)
Subject 50th Anniversary of Yuri Gagarin's Space Flight and the Launch of the First Spacecraft to Venus
Width 29.0 mm
Height 54.0 mm
Denomination 1.50 BGL
Number in set 2 (show set)
Layout/Format miniature sheet of 2 of 2 designs
Perforations 12.5 by 12.5
Stamp issuing authority Bulgaria Posts PLC
Printer Bulgarian Philately and Numismatics