Columbia subject headings:
Ivory industry--Tanzania--Zanzibar--History.
Slave trade--Tanzania--Zanzibar--History.
Spice trade--Tanzania--Zanzibar--History.
Zanzibar--Commerce--History--18th century.
Zanzibar--Commerce--History--19th century.
Harvard subject headings:
Ivory industry--Tanzania--Zanzibar--History.
Slave trade--Tanzania--Zanzibar--History.
Spice trade--Tanzania--Zanzibar--History.
Zanzibar--Commerce--History--18th century.
Zanzibar--Commerce--History--19th century.
Princeton subject headings:
Ivory industry--Tanzania--Zanzibar--History.
Slave trade--Tanzania--Zanzibar--History.
Spice trade--Tanzania--Zanzibar--History.
Zanzibar--Commerce--History--18th century.
Zanzibar--Commerce--History--19th century.