Columbia subject headings:
Laos--History--18th century.
Laos--History--19th century.
Laos--Relations--Thailand.
Laos--Relations--Vietnam.
Harvard subject headings:
Laos--Foreign relations--Thailand.
Laos--Foreign relations--Vietnam.
Laos--History.
Thailand--Foreign relations--Laos.
Thailand--Foreign relations--Vietnam.
Vietnam--Foreign relations--Laos.
Vietnam--Foreign relations--Thailand.
Princeton subject headings: