Columbia subject headings:
Slave trade--Philippines--Sulu Archipelago--History.
Sulu Archipelago (Philippines)--Commerce--History.
Sulu Archipelago (Philippines)--History.
Harvard subject headings:
Slave trade--Philippines--Sulu Archipelago--History.
Sulu Archipelago (Philippines)--Commerce--History.
Sulu Archipelago (Philippines)--History.
Princeton subject headings:
Sulu (Philippines)--Economic conditions.
Sulu (Philippines)--Foreign economic relations.