Columbia subject headings:
Ibadites--History--To 1500--Congresses.
Ibadites--Oman--History--Congresses.
Harvard subject headings:
Ibadites--Congresses.
Islam--Oman--History--Congresses.
Islamic sects--Oman--Congresses.
Oman--History--Congresses.
Oman--Religious life and customs--Congresses.
Oman--Social life and customs--Congresses.
Princeton subject headings:
Ibadites--History--To 1500--Congresses.
Ibadites--Oman--History--Congresses.