Columbia subject headings:
Postmarks--Collectors and collecting--Turkey.
Postmarks--Turkey--History--Catalogs.
Harvard subject headings:
Names, Geographical--Turkey.
Postmarks--Collectors and collecting--Turkey.
Postmarks--Turkey--History--Catalogs.
Princeton subject headings:
Cancellations (Philately)--Turkey--Catalogs.
PTT Müzesi--Catalogs.
Postal service--Turkey--History.
Postmarks--Turkey--Catalogs.