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.

BG037.18

Country / Post Bulgaria
Date of Issue 5 December 2018
Primary theme Literature, Press and Comics
Religions & beliefs (Saints)
Subject 140 Years since the foundation of Sts. Cyril and Methodius National Library
Width 54.0 mm
Height 29.0 mm
Denomination 1.50 BGN
Number in set 1
Layout/Format sheet of 20
Perforations 13 by 13
Stamp issuing authority Ministry of Transport, Information Technologies & Communications
Printer Bulgarska Philatelia & Numismatika