Columbia subject headings:
Agriculture, Prehistoric--Iraq--Congresses.
Iraq--Civilization--To 634--Congresses.
Rain and rainfall--Iraq--Congresses.
Harvard subject headings:
Agriculture, Prehistoric--Iraq--Congresses.
Iraq--Civilization--To 634--Congresses.
Rain and rainfall--Iraq--Congresses.
Princeton subject headings:
Agriculture, Prehistoric--Iraq--Congresses.
Iraq--Civilization--To 634--Congresses.
Rain and rainfall--Iraq--Congresses.