Columbia subject headings:
Hejaz (Saudi Arabia)--Economic conditions.
Industries--Saudi Arabia--Hejaz--History.
Islamic Empire--History--622-661.
Occupations--Saudi Arabia--Hejaz--History.
Harvard subject headings:
Hejaz (Saudi Arabia)--Economic conditions.
Industries--Saudi Arabia--Hejaz--History.
Islamic Empire--History--622-661.
Occupations--Saudi Arabia--Hejaz--History.
Princeton subject headings:
Occupations--Arabian Peninsula--History.