6[1]Cropper, M. and Griffiths. The interaction of population growth and environmental quality[J] . American Econosnic Review, 1994, 84: 250~254.
7[2]Grossman. G. and A.B. Krueger. Environmental Impacts of a North American Free Agreement[M]. in P. Garber(Ed. ), The US-Mexico Free Trade Agreement, Cambridge MIT Press, 1994.
8Boyce.Inequality as a cause of environmental degradation[J].Ecological Economics,1994,11:169-178.
9Torras,Boyce.Income,inequality and pollution:a reassessment of the environmental Kuznets curve.Ecological Economics,1998,25:147-160.
10Scruggs.Political and economic inequality and the environment[J].Ecological Economics,1998,26:259-275.