Writer : هارولد ا.درگن ؛
Journal:پیام یونسکو»مرداد 1356 - شماره 93 (4 page(s) - From 14 to 17 )
Keywords:خاکزمینآببیابانآبیاریآمریکاشوریکشاورزیخشکسالی
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