Columbia subject headings:
Osman I, Sultan of the Turks, 1258-1326--Congresses.
Turkey--History--Osman I, 1288-1326--Congresses.
Harvard subject headings:
Osman I, Sultan of the Turks, 1259-1326--Congresses.
Turkey--History--1288-1453--Congresses.
Princeton subject headings:
Osman I, Sultan of the Turks, 1258-1326--Congresses.
Turkey--History--1288-1453--Congresses.