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.

All registered stamps issued by Bulgaria in 2011

The 2011 issuing programme is not available.
  1. Bg041.11-80
    Wns Number
    BG041.11
    Country / Post
    Bulgaria
    Date of Issue
    November 17, 2011
    Subject
    Christmas 2011
  2. Bg042.11-80
    Wns Number
    BG042.11
    Country / Post
    Bulgaria
    Date of Issue
    December 01, 2011
    Subject
    120th Anniversary of the Military Medical Academy