Instance of: http://www.w3.org/2004/02/skos/core#Concept
Subject Field Subject Field/2011
Is Reference of Unused postage, revenue and similar stamps-en#Sense
Francobolli, marche da bollo e simili, non obliterati-it#Sense
Timbres-poste, timbres fiscaux et analogues, non oblitérés-fr#Sense