8David Arnold,Famine:Social Crisis and Historical Change(Oxford:Basil Blackwell,1988),p.15.
9R.K.Hitchcock,“The Traditional Response to Drought in Botswana,”in Madalon T.Hinchey,ed.,Symposium on Drought in Botswana(Gabarone,Botswana:Botswana Society in collaboration with Clark University Press,1979),p.92.
10Erika Bourguignon,“An Assessment of Some Comparisons and Implications,”in Bourguignon,ed.,Religion,Altered States of Consciousness,and Social Change(Columbus:Ohio State University Press,1973),pp.326-327.
