Natural disasters: causes and effects. Lesson 8--desertification.
Perez
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WASH, Arlington, Virginia, USA.
Thompson
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P
D000383:Agriculture; D000822:Animal Husbandry; D002980:Climate; D003710:Demography; D003906:Developing Countries; D004190:Disasters; D004777:Environment; D006801:Humans; D014881:Water Supply