Columbia subject headings:
Istanbul (Turkey)--On postage stamps--History.
Postage stamps--Turkey--History--20th century.
Postage stamps--Turkey--History--21st century.
Harvard subject headings:
Istanbul (Turkey)--On postage stamps--History.
Postage stamps--Turkey--History--20th century.
Postage stamps--Turkey--History--21st century.
Princeton subject headings:
Istanbul (Turkey)--On postage stamps--History.
Postage stamps--Turkey--History--20th century.
Postage stamps--Turkey--History--21st century.