Columbia subject headings:
Harvard subject headings:
Distress signals
Legislative hearings
Picture interpretation
Vietnam War, 1961-1975--Missing in action--United States
Vietnam War, 1961-1975--Prisoners and prisons, North Vietnamese
Princeton subject headings:
Distress signals.
Picture interpretation.
Vietnam War, 1961-1975--Missing in action--United States.
Vietnam War, 1961-1975--Prisoners and prisons, North Vietnamese.