Columbia subject headings:
United States--Foreign relations--Vietnam.
Vietnam War, 1961-1975--Missing in action--United States.
Vietnam War, 1961-1975--Prisoners and prisons, North Vietnamese.
Vietnam--Foreign relations--United States.
Harvard subject headings:
United States--Foreign relations--Vietnam.
Vietnam War, 1961-1975--Missing in action--United States
Vietnam War, 1961-1975--Prisoners and prisons, North Vietnamese
Vietnam--Foreign relations--United States.
Princeton subject headings:
United States--Foreign relations--Vietnam.
Vietnam War, 1961-1975--Missing in action--United States.
Vietnam War, 1961-1975--Prisoners and prisons, North Vietnamese.
Vietnam--Foreign relations--United States.